The flexibility of three reflux modes including overall reflux, gradual reflux and last stage reflux for propane compressor in C3/MRC liquefaction process is simulated respectively by dynamic simulation, on which basis high pressure control and low pressure control are added, respectively. In this way, the influence on liquefaction process and the response speed of the controller by changing the settings of controller can be analyzed. It is indicated that the high pressure control of gradual reflux can meet the demand of better stability and faster response in liquefaction process.