A weak-reflection fiber Bragg grating (WFBG) array has been widely concerned due to its characteristics such as single fiber tensile strength and large-scale multiplexing in recent years. These characteristics make it have potential application value in large-scale structural health monitoring and very-low-frequency (VLF) underwater acoustic signal detection. In this paper, the fabrication, demodulation and application progress of WFBG arrays are systematically reviewed. In the fabrication of WFBG arrays, the grating device is mainly with the drawing-tower Talbot and phase mask technology. In the selection of optical fibers, there are ultraviolet transparent coated fibers, cerium doped fibers, and so on. In the term of signal demodulation, it can be roughly divided into four demodulation technologies: time domain wavelength, frequency domain, microwave photons and matched interference. In the term of application, WFBG arrays can be used as a laser device or as a sensor for monitoring.