In current vacuum sanitation systems, a significant portion of the air consumed by the present vacuum sanitation systems was wasted due to improper settings of the same propulsive force, and the time of vacuum suction was set by the maximum amount of excreta, for sanitation operation of low and medium amount of pollutants at high frequency. According to the characteristics of vacuum suction and discharge system, the method of air consumption adjustment was studied for the vacuum sanitation system. Among which, the air suction flowrate was measured by an isothermal discharge method of the vacuum generator. On the basis of the experimental data of flowrate of the vacuum suction and discharge system, the flowrate characteristic parameters were derived by leastsquare fitting method, the pressure response process was simulated for vacuum collection tank and the response model of sanitation system was obtained. Therefore, the vacuum degree and sewerage force were adjusted by changing the air supply time and air consumption. The variable vacuumdegree design saves more than 30 percent of the energy supply in comparison with current vacuum sanitation devices, which displays excellent prospect in application and development.