The radical principle of a POlarization- independent optical isolator using YVO4 wedge is presented in this paper. The formula of the insertion loss and isolation are obtained by Jones Matrix and the configuration of the isolator is given. The authors have manufactured this kind of isolator and the experiment showed that a fiber to fiber insertion loss was 1. 04 dB,the isolation was 42 dB, the return loss was 44. 3 dB, the polarization sensitivity was less than 0. 2 dB, and the bandwidth was more than 40 nm. The dimension of the isolator is 10×10×40 mm3.