The radially polarized light has gotten wide attention due to its special polarization property.Based on coupled-mode theory,a numerical algorithm that computes the structures of the multi-layer grating is programmed by Matlab.The multi-layer grating model is theoretically simulated with this algorithm.According to the simulation,a radial polarization reflection cavity mirror is designed,which includes 1000 nm grating period,70 nm groove depth,0.5 of duty cycle and 35-layers Ti2O5/SiO2,and the sample of radial polarization reflection cavity mirror is fabricated by micro-nano processing technology.This mirror is applied to the Nd∶YAG laser,the output power up to 12.6 W,the purity of polarization exceed 96% radial polarization beams are obtained.