[Background] Due to the aggravating harm of petroleum-based plastic products to humans and the environment, polyhydroxyalkanoates (PHA) are becoming increasingly popular as new biodegradable plastic materials. However, the high production cost restricts the popularization and application of PHA. Screening the strains with high PHA yield for mass production is a key solution to this problem. [Objective] To explore the strain resources capable of synthesizing PHA and screen out and identify the high PHA-yielding bacteria from extreme environments. [Methods] The strain was isolated and purified by nile blue A plate culture and PCR methods. The 16S rRNA gene was sequenced for the identification of the strain and the construction of the phylogenetic tree in MEGA 6.0. Finally, the accumulation of PHA in the strain under different conditions was quantified by Nile red staining and gas chromatography. [Results] A strain with high yield of PHA was isolated from the garbage sediment of a saline-alkali land. The amplification of PhaC confirmed that the strain had the ability to synthesize PHA. Based on the 16S rRNA gene, the strain was identified as Pseudomonas brassicacearum and named NP-2. Furthermore, the culture conditions of strain NP-2 were optimized and the maximum accumulation of PHA reached 3.78 mg/mL at the time point of 48 h. [Conclusion] NP-2 belongs to P. brassicacearum and has high production of PHA. This study provides resources of high PHA-yielding strains in extreme environment for the production of PHA and accumulates data for further mining high PHA-yielding strains.