The invention relates to a strain of Providencia rettgeri L1 capable of efficiently degrading petroleum and an application thereof. The strain is preserved in China General Microbiological Culture Collection Center (CGMCC) on September 26, 2018, an address is Institute of Microbiology, Chinese Academic Sciences, No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and a strain preservationnumber is CGMCC No.16526. According to the invention, the strain of Providenia has a petroleum hydrocarbon degradation function, has differential selectivity on degradation of four components in petroleum, especially has a very remarkable degradation effect on n-alkanes of one of the petroleum components, can be applied to treatment of petroleum pollutants, and has a wide application prospect.