90 degree optical hybrid is the key part of space coherent optical communication and the high efficient mixing technology is an effective means to achieve great detect sensitivity. Most of optical components in optical hybrid are sensitive to polarization state, therefore, the polarization state of incident light will affect the function of hybrid. Through an theoretical analysis and simulation of the performance of hybrid whose incident light is linearly or elliptically polarized light, the result shows that the heterodyne efficiency of hybrid reaches its maximum when incident light is 45°linearly, and the change of polarization orientation can decrease the optical power entering I branch, making the heterodyne efficiency declines. Degree of polarization will increase phase difference of both branch which is orthometric in hybrid, causing the process of phase locking more difficult. Moreover, the effect of deviation of directivity of wave plate on hybrid performance is studied, for 1/4 wave plate, its deviation will change the power allegation and phase error of IandQ branch, but for 1/2 wave plate, phase error cannot be brought in, but it will change the direct current(DC) component of branch. The above polarization state changes will not bring additional phase error in I branch, ensuring the normal functioning of hybrid. This study gives a theoretical foundation to the design of space optical hybrid.