Aiming at the low output precision and easy to interfere of the optical fiber Fabry Perot (F P) sensor in the applications,a dual wavelength stabilization system in which two orthogonal signals are outputted by DWDM is proposed.The stable optimization model of dual wavelength optical fiber F P sensing system was established based on DE algorithm.A higher orthogonal precision sensing system was designed and the orthogonal experiment scheme of sensing system was built.The orthogonal output characteristics and orthogonal error of sensing system were studied.The results show that the differential evolution(DE) algorithm is fast in running and the global optimal solution can be attained in shorter run time.The error is less than 10-3.It can be used for the structural optimization design of optical fiber F P sensor.The designed sensing system has higher orthogonal output precision. When the length of F P cavity changes from -1～1 μm,the orthogonal error of sensing system is all less than 6% and the phase difference of two light waves is approaching to π/2.It has high stability and anti interference ability, and can meet the practical requirements.