Surface plasmons is the surface electromagnetic modes stemmed from the strong coupling between light waves and the collectively oscillating free electrons inside metal surfaces, featuring by at least two novel properties. One is the subwavelength light field propagation capability beating the conventional diffraction limit, the other is the extremely electromagnetic field (energy) concentration down to the nanoscale. However, the two properties above make metal-based plasmonic resonances rather lossy especially in the optoelectronic wavelength regime. As one of most promising plasmonic materials, alkali metals possess a couple of unique properties, such as the simplest electronic structure, relatively low free carrier density as well as weak interband optical transition, which suggest that alkali metals may possess lower optical damping rate compared to the conventional noble metals. In addition, the distinctly low melting point makes alkali metals more flexible for fabrication and/or multi-dimensional manipulation, making them to be alternatively rising-star plasmonic materials that may break through the optical loss limit of noble metals.In this review, we focus on the new plasmonic materials alkali metals. The paper is organized as four sections. We firstly give an overall introduction on the development and brief history on the history and revival of the field of plasmonics. In addition, the basic physical concept, crucial problems as well as the bench-mark progresses and so on are also outlined in the introduction.Firstly, we mainly introduces the basic optical properties of alkali metals from the common optical properties to the unique features. The detailed demonstration started from common optical properties of metal-based plasmonics, such as the general physical model of free carrier electron gas, the intrinsic elementary excitations, as well as the two types of plasmonic optical modes of the metal-based plasmonic materials, the Surface Plasmon Polaritons (SPP) and the Localized Surface Plasmon (LSP) modes. More specifically, two aspects of the most important plasmonic properties, called as the dispersion properties and optical loss properties are quantitatively summarized, with quantitative data of alkali metals (with respect to conventional noble metals) included and discussed in details.Then, we mainly focus on the research status and relevant theory of the optical loss of metal-based plasmonic systems. The first sub-part is the overview of the current status of plasmonic loss of metal-based systems in the field of plasmonics, in which a couple of potential strategies on fighting with the pronounced plasmonic optical loss are summarized, such as the extra introduction of gain media, photonic optimization of plasmonic structures as well as decrease of the intrinsic optical loss of plasmonic materials, etc. The second sub-part introduces the theoretical models and descriptions on the optical loss of alkali metal based plasmons, in which at least four underlying optical damping mechanisms are included. In addition, the advantages and disadvantages (and/or limitations) of different models are discussed as well.At last, the recent progresses on alkali metal plasmon based nanophotonic devices are summarized. In this section, the unique physical and chemical properties of alkali metals, as well as a variety of fabrication processes for the target highly active metals are analyzed in details, based on which two representative works of most recent advancements on alkali metal plasmons are discussed. The first work is the sodium metal based optical devices with extremely low optical loss. To overcome the high chemical activity of alkali metals as well as the poor quality and/or tough fabrication procedures of conventional physical vapor deposition methods, the authors reported the thermo-assisted spin coating and encapsulation process for sodium metal film fabrication. By fully utilizing the relatively low melting point (<100 ℃), the ultrasmooth optical substrate and meanwhile as the encapsulating media (with surface roughness<1 nm) as well as fine thermal control for liquid metal solidification, they enable a high quality sodium metal film encapsulated by glass cover. By combing the extremely low intrinsic ohmic loss of sodium metal film as well as the high quality InGaAsP quantum well and gap plasmon optimizations, the sodium-based plasmonic nanolasers enable a record threshold room temperature lasing at telecom wavelength (142 KW/cm² at 1 257 nm). The second work focus on the lithium metal. By combing the unique plasmonic properties as well as the energy storage features of lithium metals together, the authors propose a battery based research platform for active plasmonics. Based on the above platform, they demonstrate the electrochemically driven optical switch between two types of plasmonic resonances as well as a plasmon based in operando monitoring for lithium metal battery.The last section is summary and prospective. In this section, the authors mainly focus on the prospective part for the near future study, which are in details discussed in three aspects, i. e., how to modify the theoretical models, how to improve the fabrication procedures, as well as the precise optical characterization and encapsulation issues. The solutions to all these issues can definitely help us to approach the underlying physical mechanism and physical limit of the optical loss of alkali metals. In addition, a couple of high performing alkali metal based nanophotonic structures and/or devices can be suggested in the future, which may essentially push forward the cognitive boundary condition of plasmonics as well as the potential breakthrough of subwavelength integrated optics.