To address the issue of low control aeeuracy caused by treating the pipeline between two controlvalves as a single control model in high altitude platorm simulation system, the elects of pipe diameter, inletlength, outlet length, and elbow type on the flow parameters of high alitude platform pipeline system wereanalyzed using Fluent solt ware.lt provides theoretical support for the development of high precision controlmodels.The results show that pipe diameter, inlet length, and elbow type have significant effects on the flowparameters,Pipe diameter and inlet length inereased, the variation in flow parameters deereased,And the changeof flow parameters in 4$° elbow pipes was greater than that in 90° elbow. When pipe diameter inereased, pipelength eoeffieient for mutation loeation in inlet was found to be 0.8 -.0.9, while mutation loeation for 45° elhowwas approximately 0. 1 , and for 90? elbow, about 0, 15 ..0,27, When inlet length inereased, mutation position ofinlet was about 0.35 ..0.95.The mutation location of the 45 elhow was found to be approximately 0.05-0.084,and for 90° ellbow, about 0.1.The inerease in the length of outlet would only alleet the mutation position ofoutlet, which was about 0,04 ~.0,44, Based on $pearman correlation analysis, the primary and secondary orderaffeeting mutation position of inlet and outlet is : inlet length > pipe diameter > outlet length > elbow type, inletlength > pipe diameter > elbow type > outlet length.