Biosurfactants have the advantages of non-toxic, biodegradable, and these properties are particularly suitable for the biological viscosity reduction of oil, oil recovery enhancement, and the bioremediation of heavy oil polluted soil. By using Dietzia maris bacteria that are the only one could produce extracellular biosurfactants in the sole carbon source medium radiated by the different doses of ¹²C⁶⁺ ion beam, a positive mutant strain YR9 is screened from the large number of mutants. The studies show that the best mutation rate of the bacteria is obtained with the 25Gy dose irradiation, resulting in surface active dose of 6336.45U/mL. Comparing with the strain without mutagenic treatment, the improvement of 2.65-fold is achieved; it almost able to completely degrade n-C₅, n-C₆, n-C₁₆, toluene, quinoline, carbazole, o-xylene, p-xylene, gasoline, naphthalene, catechol, however for n-C₅, naphthalene degradation is lower. The physical and chemical properties of the surface active agent produced by the bacteria are analyzed, its products are identified, and the condition produced surface active agent is optimized.