Abstract: When the low-concentration gas is used for power generation, the moisture in the gas at the outlet of the water-ring vacuum pump is larger, the liquid water entering into the power generator unit will increase the heat consumption, rust the equipment and affect the unit boot rate and power generation efficiency. To counter these problems, analysis was made on the principle and process technology of the commonly-used dewatering methods, the dewatering efficiency and resistance factors were all taken into overall consideration, the wire-mesh dewatering scheme was put forward and relevant design was carried out so as to study the influence of the dewatering effect and resistance on the power generation efficiency. The study results showed that the wire-mesh seperator can effictively remove the moisture in the gas, so it has better economic benefit.