Recently, many microorganism strains which have capacity ofbiofilm formation are interested in applying in pollution treatment. Especially, application these organisms is considered as new and effective method to treat petroleum oil contaminant. The potentially biofilm-forming and biosurfactant-producing as well as highly diesel-degrading bacterium 82 was isolated from petroleum storage tanks in Do Xa, Hanoi. By analysis of bacterial 16S rRNA gene sequence, the strain 82 was classified as Rhodococcus sp. with the assession number is JQ567804. Several optimal conditions for biofilm formation and biosurfactant activity such as temperature 30oC, pH 7, NaCl concentration 0.5 percent were determined. As the result, using these optimal conditions to incubate the bacterium, the optical density at 570 nm of formed biofilm is about 18 and the biosurfactant activity is 65 percent. And under these optimal conditions, after 5 day-incubation supplemented with 1 percent diesel oil, the 82 under biofilm form degraded 72 percent of total diesel oil. The results in this study suggest thl: potential usefulness of dominating a well biofilm-forming, biosurfactant-producing and diesel oil-degrading bacterium 82 to achieve efficient and sustainable bioremediation of petroleum polluted water.