In order to solve the problem that the traditional laser illuminator optical system only realizes the beam collimation and the beam uniformity is poor, the miniaturization of the laser illuminator optical system is studied. Expanding the laser beam, the binary optical elements B1 and B2 for beam homogenization and collimation are designed by Gerchberg-Saxton (GS) improved algorithm. According to the principle of constant optical power, the coordinate transformation formula of beam homogenization is established, and the macroinstruction is written in ZEMAX to design the optical system of aspheric lens group. The results show that the system can make the beam uniformity reach 96.2%, the divergence angle is better than 0.25 mrad, and realize the miniaturization of the optical system (the optical system size is 110 mm×42 mm×42 mm).