The aim of this paper is mainly to study the main coal-dust pollution sources in the coal preparation plants of Ping Shuo Branch of China National Coal Group. Through the combination of many measurement data with numerical simulation of gas-solid two-phase flow, dust precipitation mechanisms have been gained for the feeder in Ping Shuo Coal Preparation Plant. Dust pollution of the feeder is caused by the positive pressure of the induced feeding wind-flow and the bad seal itself. Firstly, the durable flexible seal material is used to seal up the feeder. Secondly, the seal guide-chute with the dust collector is installed on the belt. Finally, the air volume and the pressure of the dust collector are determined by means of numerical simulation, and the reasonability of the plan is explained from the angle of the dust control mechanism. The main technical parameters of the dust control plan, such as the seal guide-chute length, and the air volume and the pressure of the dust collector, are determined through the numerical simulation. The simulation result and the actual result verify the above dust control plans. The study methods and results provide a guide for the dust control in a certain similar business.