Based on the flow-line and simultaneous multiple surfaces (SMS) design method in nonimaging optics, a design method for LED collimator with low divergence angle, good uniformity and high luminous efficiency is presented. The divergence angle ±90° of a Lambertian source is reduced to ±45° by using the compound parabolic concentrator (CPC) reflector, and then the outgoing lights are collimated by the SMS reflector. A theoretical optical ratio is derived from the entendue of the collimator, and top width, top luminous efficiency and top uniformity are introduced to characterize the quality of the collimated lights. The simulation results show that the divergence of the collimator is less than ±2.26°, the total luminous efficiency is up to 0.79, the luminons efficiency error is less than 2.5% compared with theoretical luminons efficiency, the 0.9 top-flat uniformity is more than 0.9, and the top-flat luminous efficiency is about 0.56, it has good results.