Two-layer spherical retroreflector which is based on one-layer spherical retroreflector was proposed. On the basis of the object-image relationship of refracting spherical surface and ray tracing theory in vector field,the interrelation between refraction index and radius of curvature of each layer was figured out,the relations among divergence angle,incident height and spherical aberration were induced. Two-layer spherical retroreflector and its improved form were designed by ZEMAX,the field of view angle is ±60°,and the working wavelength is 632.8 nm. The root mean square spot diameters of the two kinds of spherical retroreflectors in different fields are all less than Airy disk diameter 4.632 μm,and the maximum values of spherical aberration is only 0.045 mm,which means that the largest divergence angle of the reflected light is less than 0.1 mrad. The simulation results show that,the luminous flux that the reflected light reaches on the receiver respectively can approach 48.769 lm and 44.249 lm ,the incident luminous flux is 54.594 lm,so the reflected efficiencies respectively are 89.33% and 81.05%.