Storage reliability of Fiber Optical Gyroscopes(FOGs) was studied based on a multivariate degradation data method. Firstly, the dependence of multivariate performance degradation data was analyzed by means of the covariance matrix and the failture probability of products was characterized by a joint probability density function. From that, an universal method to evaluate product reliability via multivariate degradation data was achieved. Based on the characteristics of FOGs, the bias, bias stability and factor change were selected as degradation parameters, and a related storage test was carried out to obtain the performance degradation data. The storage reliability of FOGs was assessed by multivariate degradation data. Obtained results show that, in ambient environment of 60 ℃, the storage life is about 32 800 h and 13 200 h as considering the dependence and independence of FOGs’ multivariate degradation data,respectively.These data demonstrate that the reliability evaluating method from multivariate degradation data is more reasonable,and it can be extended to other product assessments with multivariate degradation parameters.