Abstract: The problems such as poor wettability of ultrafine coal dust (mass fraction of coal dust with a particle size less than 5 μm is not less than 50%) have seriously restricted the effect of mine dust control. Based on this, a new type of highly efficient and biodegradable dust suppressant was studied and designed. Fourteen common surfactants were selected. The surface tension tester, contact angle tester and sedimentation test were used to test the 14 surfactants, and three single surfactants were seleted. The single surfactants seleted were compounded in pairs. Three compounded solutions were selected for laboratory spray dust suppression simulation tests, five-day biochemical oxygen demand (BOD₅) and chemical oxygen demand (COD) tests to determine the final dust suppression agent formula. Infrared spectroscopy was used to characterize the changes of oxygen-containing functional groups on the surface of coal dust after treatment with dust suppressant, as well as the changes of surface potential of coal before and after the action of dust suppressant. The results show that water has poor wettability for ultrafine coal dust, while the dust suppressant can improve the wettability of ultrafine coal dust. The comprehensive determination of the dust suppressant formula is a mixture of coconut oil diethanolamide (CDEA) and secondary alkyl sodium sulfonate (SAS−60), with the two in a 4∶1 mass ratio (mass fraction is 0.05%). The biodegradability value (BOD₅/COD) of the dust suppressant reaches 0.4, and it belongs to the biodegradable type, meeting the standards for coal mine wastewater treatment. The COD also meets the requirements of anaerobic fermentation technology, thereby promoting the release of organic matter and providing raw materials for biological manufacturing. The dust suppression agent has a dust suppression rate of over 80% for ultrafine coal dust, and the maximum dust suppression efficiency can reach 90%. After being treated with the dust suppressant, the oxygen-containing functional groups on the surface of coal dust increase, the hydrophilicity is enhanced, and the electronegativity is weakened, indicating that the dust suppressant can adsorb on the surface of coal dust, thereby achieving the dust suppression effect.