Abstract: Based on the analysis about characteristics and mechanism of road dust raising in open mine，the components of dust-depressor was determined.The monomer and its concentration range were initially determined by monomer selection experiments of moisture agent，coagulation agent and surfactant.Based on the orthogonal test，and regarding the water loss rate as evaluation index，the optimal formulation was determined and its performances in the natural environment including moisture releasing and adsorption and wind resistance were tested.Results show that the formula obtained by experiments has good performance of moisture absorption and water retention，and it also has a good dust preventing and controlling performance due to its high surface strength and consolidation under dry conditions.With a wide range of material sources，simple preparation and low costs，it has a good application prospect.

Key words: Open-pit mine, Road dust-depressor, Mill dust, Water loss rate