A new type of dust-collecting and dedusting system with air curtain was developed to solve the problems of the dust-prevention in mine tunnel. The speed of air-curtain fan, the structure size and pressure of dedusting duct are the critical factors, which effect dust control of the whole system. In order to achieve optimal efficiency of dust control, the simulation was conducted with FLUENT(computational fluid dynamics software) to analyse the air-curtain fan surface path lines and dust particle tracks at different wind speeds of air curtain fan, dedusting duct diameters and outlet pressures. We obtained the law of fan speed, the diameter and outlet pressure of dedusting duct, which effect the whole system on dedusting. This law would play a guiding role on the structural optimization of dust-collecting and dedusting system with air curtain.