Based on the principle of laser ranging system and the optical characteristics of the reflective system,an all reflective laser ranging system with common aperture was designed by introducing optical circulator. The laser emitting system and receiving system share one 4× telescopic system. On this basis,the laser emission system adds one 5× telescopic system and the laser receiving system adds a laser focusing system. By the tolerance analysis and reliability analysis of the system,the processing materials,processing methods,as well as the precision of processing and installation and the feasibility of practical application were determined. In order to save costs,shorten the processing cycle,reduce the difficulty of alignment,the system mainly adopts quadric surface mirrors. Simulation results show that the whole system had good image quality,high energy concentration,compact structure and light weight,which can meet the requirements of practical application.