Aiming at the disadvantages of the existing measuring system which measures the consistency between the platform and the axes of the standard pipe of the multi-barrel rocket launcher, design a set of new optic-electrical measuring system. Introduce use of the autocollimator, reticule and mirror to simulate the axes of the standard pipe, and then apply the photoelectric rotary encoder to measure the consistency of the platform of the multi-barrel rocket launcher. The thesis introduces the system and carries out accuracy analysis and simulation. Result shows that the system has advantages of easy operation and high precision, and its implementation is good.