Abstract: With the improvement of mechanized mining, the amount of coal dust produced also increases.In view of the increasingly serious problem of dust pollution in the underground working environment of coal mines, the surface tension of solution containing green high-efficiency biological dust suppressant (EMI) with different mass fractions was measured.The wetting effect of EMI solution with different mass fractions on coal dust with different particle sizes was studied using the indicators of contact angle, coal dust wetting rate, coal dust moisture absorption and water retention of coal dust with different particle sizes were taken as indicators.The experimental results show that as the mass fraction of EMI dust depressant in the solution increases, the contact angle of coal dust decreases gradually with the increase of mass fraction of EMI dust depressant in the solution, the time required for complete settlement of coal dust decreases gradually, the moisture absorption increases, the water retention gradually increases, and the hardening property of coal samples is larger after water loss.Through analysis, the mechanism of EMI wetting coal dust is obtained: reducing the surface tension of water; increasing the wettability of the solution; reducing the water loss, and improving the evaporation resistance of the solution.