Abstract: To meet the sealing test requirements of pipeline-like systems, a pressure maintaining method based on temperature and pressure changes was presented. The influencing factors of leakage rate detection for small pipelines were analyzed. A temperature compensation model was proposed. The pipeline leakage rate detection indicators, the required detection time, and the requirements for temperature and pressure sensor parameters were analyzed. Through tests on a pipeline-like system, the verification of the leakage rate detection of the small pipeline measured by the proposed method was completed. It is shown that the pressure maintaining method based on temperature compensation model has good accuracy for leakage rate detection. The results may provide ideas for solving the leakage rate detection of working fluid resupply pipelines in space system.