Abstract: Liquid oxygen filling is of extremely important significance for rocket launches. It not only relates to the performance of the rocket and the success of flight missions, but also directly affects the safety and efficiency of launches. Therefore, during the rocket launch process, great importance must be attached to liquid oxygen filling work, and scientific and effective measures must be taken to ensure the smooth progress of the filling process. The flow rate of liquid oxygen filling is a crucial parameter in the filling process. Therefore, there are high requirements for the safety, accuracy, and automation control of the liquid oxygen filling flow rate. In view of the control difficulties such as multi-parameter linkage, nonlinearity and large lag in the flow regulation of the liquid oxygen filling system, a liquid oxygen filling flow regulation algorithm Based on Multi-Module Coupling Flow Control Algorithm（BMMCA） is proposed. The algorithm couples multiple modules such as automatic pressure regulation of the storage tank, throttling flow regulation, and adaptive regulation of the target pressure, achieving adaptive and precise regulation of the flow during the liquid oxygen filling process. The test results show that the BMMCA algorithm proposed has the characteristics of fast response speed, short transition process and good target value tracking. It achieves the purpose of intelligently regulating the flow in different filling stages, and can better meet the demand for liquid oxygen filling. It provides technical support for the fully automated filling process of liquid oxygen and the possibility for the intelligent launch site to comprehensively control the ground equipment for liquid oxygen filling.