An alkaline lipase strain of Pseudomonas aeruginosa HFE733 was isolated from soil samples of domestic waste. The alkaline lipase from P. aeruginosa HFE733 was purified and characterized. The enzyme was purified 9.97-fold by means of ammonium sulphate precipitation, Sephadex G-25 and diethylaminoethyl (DEAE) cellulose chromatography. Purified alkaline lipase protein was analyzed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), the molecular mass was 51.0 kDa. The enzyme exhibited maximum activity at 40 °C and pH 8.5. The enzyme is stable at pH 7.0–8.5. It was remarkably activated by some metal ions and chemical reagents, such as Fe³⁺, Al³⁺, β-mercaptoethanol, cysteine, DL-dithiothreitol (DTT), Tween 80 and Triton X-100, but suppressed by sodium dodecyl sulfate (SDS) at 10 mmol/L. The P. aeruginosa HFE733 strain and lipase exhibited remarkable potential for biodegradation of oil and organics (measured as chemical oxygen demand (COD)). We demonstrated that it can be used for biodegradation of food wastewater from restaurants.