Abstract: The working principle of four-quadrant detector for laser guidance is introduced. According to the technical requirements of laser guidance and the working characteristics of four-quadrant detector, an improved method of lens design of four-quadrant detector for laser seeker is proposed. Aiming at the problem that nonlinear relationship is not easy to solve, the four-quadrant detector lens is designed by using Zemax in sequential mode, and the energy distribution of the light spot is controlled by setting operand, so that the Angle deviation of the target is linearly related to the output signal of the four-quadrant detector, which can improve the real-time detection accuracy. This method does not require uniform energy of light spots on the detector, nor does it require uniform size of light spots in each field of view, which greatly simplifies the design. The feasibility of this method is verified by simulation analysis combined with application background.