Improving the removal efficiency of fine particle is significant for the elimination of particle emission from coal-fired power plants. This work reports a combined wet electrostatic precipitator (WESP) enhanced by a novel perforated pre-charger to efficiently remove fine particle from wet flue gas. Penetration and charging characteristics of fine particle through the WESP were evaluated as a function of particle size. The collection performance was investigated under controlled gas temperatures and varied electrical conditions. Results showed that there was a maximum penetration ratio around 0.1 mu m and it decreased with the increasing applied voltage. A portion of the escaping fine particles were not charged through the WESP, and the size limit for partial charging can be reduced to 0.025 mu m when the applied voltage increased to 32 kV. Reducing gas temperature leaded to an obvious improvement in collection efficiency for particles in the size range of 0.1-1.0 pm. The test results of different electrodes showed that both the corona current and maximum collection efficiency ranked in the order of pin > sawtooth > rod. With the assistance of pre-charger, the particle charging was significantly improved and the charge amount was more than doubled. Consequently, the effective migration velocity for PM0.1, PM1.0 and PM2.5 increased by 69.9%, 65.7% and 34.2%, respectively. Actual application results showed that the average PM emission level can be reduced to 0.43 mg/m(3) by the combined WESP in a 1000 MW coalfired power plant.