Abstract: In order to solve the problem that the check valve function verification tests (TXRIS007) of multi-unit accumulators in a nuclear power plant do not meet the acceptance criteria in most cases, the one-dimensional fluid simulation software (Flowmaster) was used to establish the test model to carry out the transient calculation of different configurations, and theoretical analysis was presented based on historical data. The research shows that while only the reasonable errors of the inner diameter of the test pipelines and the measuring instruments are considered, the initial flow rate range is between 2.37 m3/h and 5.70 m3/h under the normal condition of other test influencing factors; the difference of equipment performance such as the large change of valve resistance characteristics, the actual inner diameter and pipe wall roughness of the pipeline, and the serious blockage of the common loop will lead to the large change of flow; setting a uniform minimum flow may not recognize the change of the performance of valves on the loop with higher reference flow, so it is suggested that the reference flow for different units under the same test conditions shall be calibrated based on the calculation results, and the test results shall be recorded and summarized.