Abstract: In order to evaluate the level of the failure rates of the components, a long time and material consuming is required if the sampling plans defined in GB1772-79 (its equivalent in MIL-STD-690) is used. It is almost impossible for these plans to give evaluation for a high level component. The Bayesian method used here, which determines a prior distribution based on large amount of the historical data and plentiful engineering experience, gives a new plan for tests to evaluate level of the failare rate of the components. With the prerequisite of quality assurance of the products, considerable test-time can be saved by using the plan.