Abstract: Take sodium carboxymethyl starch as main ingredient, four kinds of compound powder coal dust suppressant are synthesized on the basis of compound with bentonite, diatomite and sodium dodecyl sulfate, we research the influence of the condition change of the microwave radiation and inorganic minerals on hygroscopic and moisture resistance, cohere coagulation performance, wind resistance, thermal stability and other performance. The results show that moisturizing and bond coagulation effect of bentonite is better than that of diatomite for coal dust under same conditions, whereas, there is no significant effect on the ability of moisture absorption for both them, the best dust suppression time of four groups of dust suppressant can be up to 2 d, and there are still some water retention ability within 5 d. Microwave radiation could significantly improve the hygroscopic and moisture resistance, cohere coagulation performance, wind resistance and thermal stability of dust suppressant, besides, the highest viscosity is 22 mPa· s, moisture absorption rate is as high as 4.6% while in the 4th day, the lowest wind erosion rate is 2.06×10^-6, the oxidation decomposition temperature could up to 180 ℃.