Since the invention of the first ruby laser in 1960, after more than 60 years of research and development, laser has been widely used in various industries due to its excellent characteristics such as high directionality, high brightness, and monochromaticity. Over the years, lasers have continuously evolved and innovated to meet market demands. While there are various laser shapes and pump sources available in the market, covering different output powers, wavelengths, and pulse durations, the core components of all lasers consist of the laser gain medium, pump source, and optical resonator cavity.Firstly, the conditions for the generation of organic lasers and the energy level system are introduced. Population inversion is crucial to overcome the competition between stimulated absorption and stimulated radiation. Achieving population inversion allows excited radiation to dominate, enhancing light intensity, which is the fundamental principle of laser amplification. However, in practice, not all luminescent materials can achieve the population inversion. To achieve the population inversion, a suitable energy level system is necessary. The four-level system is more effective in achieving population inversion compared to the three-level system.Next, the paper discusses organic semiconductor gain materials, which are the foundation of organic lasers. These materials enable population inversion and light amplification through stimulated emission. Organic semiconductor lasers stand out from others due to their use of organic materials as the laser gain medium. Compared with inorganic materials, organic materials offer high tunability in photoluminescence spectra, thanks to their abundant excited-state photophysical and photochemical processes. Additionally, the weak interaction between organic molecules allows for flexible control of crystal geometry and mass crystal fabrication. Meanwhile, the complex excited-state energy level system of organic materials is inherently more favourable for constructing a four-level system for the population inversion. The paper classifies luminescent mechanisms into fluorescent materials, thermally activated delayed fluorescent materials, and phosphorescent materials, summarizing the research progress in these areas.Finally, the paper focuses on optical resonant cavities, highlighting their two main functions: firstly, to generate and sustain laser oscillation by ensuring continuous stimulation of the gain medium through radiation, thereby achieving optical amplification. Secondly, to control the quality of the output laser beam by adjusting the geometric parameters of the resonant cavity, regulating the oscillation frequency, transverse distribution characteristics, and spot size of the laser beam. A well-designed resonant cavity can produce significant optical resonance in a small space for an extended period. Various types of optical resonant cavities have been developed based on different light-confining methods. The paper introduces the types of optical resonators and discusses the research progress in organic microcavity lasers based on various resonator structures, including planar waveguide and microcavity structures. Through the regulation of organic gain materials and the parameter modulation of the resonant cavity, not only enables the realization of full-wavelength lasers but also allows for customization of the frequency, transverse distribution characteristics, and mode selection of the laser output beam. The paper aims to serve as a reference for further exploration into organic microcavity lasers with innovative resonant cavity structures.