Abstract: In order to solve the problems in the integrated assembly and adjustment process for the tank fire-control gunner field stable laser rangefinder collimator optical system, such as the low accuracy of Z axis in image stabilization system, overproof target range, overproof loading list range and different threeaxis parallelism, an integrated assembly and adjustment technology of gun sight optical system was put forward. Using optical auto-collimation method, the lens, high-precision plane-parallel mirror, long-focal-length parallel light tube and zero position instrument were adjusted to establish sighting axis zero reference, and the parallelism of three axes (sighting axis，laser emission axis，laser receiving axis) was up to the standard. The error of photomechanical elements was qualified in benchmark range. The first delivery-check qualified rate was increased from the original 60% to 95%, and the stability and reliability of the products were got promoted, which ensured the first-round hitting probability.