Abstract:  In order to meet the new requirements of particulate matter quantity monitoring in the sixth national emission regulations, it is urgent to put forward a particulate matter measurement technology with excellent accuracy and real-time correspondence adapted to the diesel engine emission environment. This paper introduces a kind of leakage current particle sensor, which uses venturi tube structure to absorb particles, and describes the value of particle concentration by the leakage current generated by charged particles in the internal concentration test area. In order to solve the problem of sensor measurement drop caused by particle deposition inside the sensor, it is necessary to understand the movement law and deposition mode of particles in the sensor, so the simulation study of the distribution law of flow field and other fields in the sensor is carried out. Based on the simulation results, the influence of particle deposition mode on the distribution of each field is studied, and the mechanism of particle deposition is obtained. The results show that the increase of temperature directly leads to the increase of three deposition rates. At the same time, the gas velocity has different effects on the three kinds of deposition velocity. The deposition velocity of electrophoretic and inertial collision is positively correlated with the gas velocity, while the deposition velocity of thermal swimming shows an opposite trend.