Abstract: Operation of the liquid-ring vacuum pump system, comprising the pump, pumped container, gas-path and valves, was mathematically modeled and numerically simulated with Flowmaster software. The correlation of the pumping conditions, including the length/radius of gas-path and inlet pressure, with the pump's properties, such as the rotation speed, impeller size and valve-opening, was investigated. The simulated results show that the pumping conditions strongly correlate with the pump's properties. To be specific, as the rotation speed and impeller size increase, the gas flow-rate increases and the pump's pressure decreases;a longer gas-path length, a smaller gas-path radius and a reduced valve-opening result in a lower gas flow-rate;as the inlet pressure increases, the gas flow-rate slightly increases, so the pump's pressure should be lower, i. e., a higher vacuum. We suggest that the simulation be of some technological interest in design of liquid ring vacuum pump system.