The present study investigates the collection characteristics or a semi-wet type multi-stage porous plate system combined with a water spray. Numerically and experimentally, collection efficiency and pressure drop were estimated with the various operation parameters such as the droplet spray, stage number. bole diameter and inlet velocity, etc. Moreover, a water spray system was adopted to prevent the reentrainment of deposited particles and especially to increase the inertia effect for submicron particles. Pressure drops for 6 stage in a case of a hole diameter of 6 mm were moderately controlled as 200 and 211 mmH(2)O showing the high collection efficiency 97.0 and 98.3% at inlet velocity 1.0 and 1.2 m/s, respectively, by the numerical simulation. For 6 stage and an inlet velocity 1.2 m/s, higher collection efficiency was estimated over 99% due to the proper water droplet spray maintaining the pressure drop of 200 mmH(2)O, experimentally.