Diffractive lenses are lightweight and exhibit loose surface tolerance, rendering them a competitive option for lightweight lidar optical receiving systems. To address the challenge of low transmittance in single diffractive lenses when the F-number of the receiving system is small, this study introduces a hybrid structure comprising a diffractive lens, collimating group, and converging group. Based on this structure, a receiving optical system with a 50-mm aperture, a full angle of view of 0.9 mrad, an F-number of 1.78, and a wavelength band of (1064±0.1) nm is designed. The analysis results of the system indicate that the root-mean-square radius of the diffuse spot is significantly smaller than the Airy spot radius, and the imaging quality is approached to the diffraction limit. Considering the diffraction efficiency of the diffractive lens and the absorption and reflection of the glass material, the transmittance of the system is calculated to be 78.2%, meeting the practical application requirements of LiDAR for optical receiving systems. Therefore, a reference for the design of diffractive LiDAR optical receiving systems is provided by this system, offering a solution to enhance transmittance and overall performance.