Drilling mud is generated during exploratory drilling and oilfield development, and consists of a mixture of soil, rock contaminated with oil, chemicals, and drilling fluid. It is very difficult and expensive to treat this waste source, so the biosurfactant produced by microorganisms is considered a highly effective biological treatment method. Biosurfactant is a bipolar compound that allows the dissolution of insoluble substances in water, creates an emulsion that helps microorganisms better contact the oil and easily decompose the contaminated oil. This study was carried out to evaluate the ability to degrade oil in drilling mud using biosurfactant produced by some microbial strains. The results showed that four microbial strains selected from Cat Ba, Hue and Vung Tau areas, namely Brevibacteria celere, Oligella ureolytica, Stenotrophomonas maltophilia and Paenibacillus mancerans have the capacity of decomposing oil in drilling mud. The highest emulsification index (E24) of the four strains after 5 days culture with shaking at 200 rpm, pH = 7.5, temperature 30°C, 1% NaCl, carbon source of saraline and DO were recorded at 73, 71, 52 and 59%, respectively. This result shows that biosurfactants are an active compound group with potential in oil pollution treatment in the Petroleum industry in particular and environmental pollution treatment in general.