The invention relates to a similar product information-based bayesian reliability evaluation method of small number samples. The method comprises the steps of (S1) carrying out similarity scoring on similar products and determining a prior sample set; (S2) acquiring prior information, which includes failure life data and pseudo failure life data of the similar products; (S3) determining a prior distribution form; (S4) checking the failure mechanism consistency of the similar products; and (S5) determining prior distribution and posterior distribution and achieving bayesian reliability evaluation. According to the method provided by the invention, the sample quantity of the small number samples is effectively improved; and the prior information includes the failure life data and the pseudo failure life data and a two-parameter bayesian reliability evaluation problem is converted into single-parameter bayesian reliability evaluation, so that the bayesian reliability evaluation accuracy of the products is effectively improved and the calculation method of bayesian reliability parameter evaluation is simplified.