The explosive initiator is one kind of sensitivity products with long life and high reliability. In order to improve the storage reliability assessment, the method of storage reliability assessment for explosive initiator was proposed based on time series model using the sensitivity test data. In the method, the up and down test was used to estimate the distribution parameters of threshold. And an approach to design the up and down test was present to draw better estimations. Furthermore, the method of shrinkage estimation was introduced to get a better estimation of scale parameter by combining the sample information with prior information. The simulation result shows that the shrinkage estimation is better than traditional estimation under certain conditions. With the distribution parameters estimations, the time series models were used to describe the changing trends of distribution parameters along with storage time. Then for a fixed storage time, the distribution parameters were predicted based on the models. Finally, the confidence interval of storage reliability was obtained by fiducial inference. The illustrative example shows that the method is available for storage reliability assessment of the explosive initiator with high reliability.