Abstract: In order to improve the collimation precision of ultra-short pulsed laser, an optical system of collimator based on auto-collimation theory was proposed. Beam spread collimation optical system providing a parallel precision of 3.2, which is illuminated by fiber coupled laser with a wavelength of 670 nm, was designed. As well as, an off-axis parabolic mirror of principal laser with the focal length of 350 mm, relative aperture of 1/5, and off-axial distance of 50 mm, was designed, and the imaging quality could reach the diffraction limit. Based on the collimating optical system and off-axial parabolic mirror, the 20 and 100 imaging systems working at wavelength of 670 nm and 800 nm synchronously were designed. An installation and alignment method based on pinhole collimation was proposed. The results of experiment illuminated by indicated light show that the image spot is even, and its resolution can reach to 4.1 m in the object space.