A scroll compressor comprises a partition plate, a compression mechanism, a capacity adjustment device and a sealing assembly. The sealing assembly isolates a back pressure chamber from a high-pressure space and low-pressure space. A first sealing portion is formed between the sealing assembly and the partition plate. The capacity adjustment device is provided with a variable pressure chamber and configured to establish or break the communication between a first compression chamber and the low pressure space by changing the pressure in the variable pressure chamber. According to the compressor, requirements for pressure in the back pressure chamber of the compressor in different load conditions can be balanced, the axial force on the compression mechanism can be reduced, the power consumption of the scroll compressor can be lowered, the system performance can be improved, and the manufacturing cost can be reduced.