Abstract: Active polarization imaging technology is a hot research field in recent years both at home and abroad, which has great value in terms of military and civilian aspects. Compared with passive imaging technology, active polarization imaging technology can remedy the deficiencies of imaging completely relying on the radiation or reflection from the target. As a result, the imaging distance and signal to noise ratio of the image can be greatly improved. Besides, by adding a light source with its parameters known, the Muller matrix of the target can be calculated according to the incident light and the output. Furthermore, the characteristics of intensity, coherence and depolarization of the light emitted or reflected from the target can be analyzed. The development of active polarization imaging technology, as well as system structure and principle were introduced. In addition, several typical polarization imaging systems, as well as their advantages and disadvantages, were presented. At the end, the future of active polarization imaging was predicted.