The work aims to put forward the retention system according to the package characteristics and give suggestions on the establishment of retention system, stress analysis and structural optimization, so as to provide reference for the mechanical safety evaluation of radioactive material transport. According to the retention characteristics of the different transport packages, the retention systems were classified into four categories:tie, baseplate, framework and array. The finite element analysis was conducted to the typical retention systems under the combined acceleration factor load condition, to obtain stress characteristics and danger zones of the packages and retention members. The retention systems in the transportation of radioactive materials were summarized, and the improvement schemes were proposed according to different retention methods. The mechanical analysis results are enveloping, and the four types of retention methods can meet the transportation requirements of most transport packages under the conditions of roads, railways and waterways, which provides a reference for the design and safety evaluation of the retention system for radioactive material transport.