In view of the difficulties in reliability evaluation of multivariate performance parameters by traditional reliability assessment methods, a reliability evaluation method based on performance degradation and D-S evidence theory is proposed. Firstly, the degradation data of each performance parameter is modeled, and their degradation models and life distributions are obtained. Secondly, D-S evidence theory is used to fuse and make decisions on the life data of each key performance parameter, and then the overall reliability index of the product can be obtained. Finally, this method is tested with performance degradation data of fiber-optic gyroscope and the storage life of it is 36 500 h. Taking the experimental data of certain type of fiber optic gyro as an example, the effectiveness of the method is verified. The result shows that this method can effectively solve the problem of reliability evaluation of multi-parameter products, and has certain reference significance for reliability evaluation of multi-parameter products.