Abstract: The electrostatic charged two phase flow field produced by a duster used in plant protection was theoretically and experimentally analyzed and investigated. Based on the analysis of the forces acting on the dust particles in a two phase flow, its kinetic equation was established and the general solution of this equation was given. The calculation of the powder velocity field produced by a practical duster was demonstrated. At the same time, this field was measured by a Laser Doppler anemometer. The calculated results and the measured data were reasonably met each other.