Terahertz (THz) waves have a good transmissivity through non-polar materials, and have no ionization effects on biomedical tissues. Therefore, it is ideal for the applications such as non-destructive testing and biomedical imaging. The imaging system based on THz quantum well photodetectors (THz QWPs) has higher imaging resolution, faster imaging speed, higher signal-to-noise ratio, and more compact structure than the imaging systems based on other detectors, as the THz QWPs have fast response, high responsivity, low noise equivalent power, and tiny size. This paper reviews the research progress of the imaging technology based on THz QWPs. And the factors affecting the core indicators of the imaging system are analyzed and summarized. Using more stable fixtures to mount the THz QWPs, improving the device response speed, detection sensitivity, array size, can improve the key performance of imaging systems effectively.