Confocal micro-measurement is a promising technology with non-contact measurement and high-precision displacement recognition capabilities, which is widely used in chip processing, high-precision instrument manufacturing, biomedicine, material chemistry, industrial testing and other fields. The two-dimensional images scanned with high accuracy along the axial position can be used for three-dimensional reconstruction. However, the scanning speed limits the rate of image acquisition. In order to overcome this limitation, researchers have proposed many methods to improve the conventional confocal microscope system. For example, it mainly includes scanning confocal microscope based on scanning galvanometer beam, confocal microscope based on digital micro-mirror device, differential scanning confocal microscope, etc. Here, this paper mainly discusses the working principle, types of objective lens, scanning methods, advantages and disadvantages, and applications of various confocal microscopes. We believe that with the upgrading of the core components of the optical system and the emergence of various accurate and efficient peak algorithms, the scanning speed of the confocal microscope will be faster; the range will be wider and the resolution will be higher in the future.