Abstract: Aiming at the problem of applying charge induction method of measuring low dust concentration is not accu- rate,this paper proposes to reduce the middle parts of current measuring pipes’ diameter,and form the contraction segment,throat segment,diffusion segment three parts,to improve the movement speed of dust particles by venturi effect,and then increase the inductive charge of electrostatic sensors. The experiments simulate the gas-solid two phase flow in the improved measurement pipeline by Fluent software,obtaining the velocity distribution of dust particles and the speed value in the throat segment. According to the mathematical model of loop static sensor,the inductance of dif- ferent pipe diameter ratios is calculated. The results show that the inductive charge on the static sensor reaches the lar- gest,when the improved pipe diameter ratio is 0. 69. Through the optimization of measuring device,the accuracy of measurement can be increased by 3% ,the measurement accuracy of low concentration dust is improved effectively.