Abstract: In order to solve the problem of inaccurate detection of small particle size dust concentration by existing cool mine dust concentration measuring device,and based on the Venturi effect and the Karman Vortex effect,the pipeline of the existing measuring device is optimized,and the throat section of the venturi pipe is proposed.A front gas sheath and a posterior gas sheath having a horizontal distance difference are added.A structure model of the improved device was established in Gambit2.4,and the model was simulated by Fluent6.3.The corresponding velocity cloud images of particles with different particle sizes were obtained,and the velocity values were read,and the relative electrostatic induction was calculated by MATLAB.The simulation results show that compared with the text tube studied by the project team,the overall electrostatic induction of the improved device is increased by 12%; When the particle size of dust is less than 10 μm,the electrostatic induction of dust with small particle size is the most obvious in comparison of inductive charge between two measuring devices,and electrostatic induction of dust with small particle size is increased by 18%.It has reference significance for designing a small particle size dust concentration measuring device.