The invention relates to a scroll compressor. The scroll compressor comprises a compression mechanism, a main bearing pedestal, a backpressure cavity and a first sealing device. The compression mechanism comprises a fixed vortex piece and a movable vortex piece. The movable vortex piece can axially move between a connection position and a separation position. At the connection position, the movable vortex piece and the fixed vortex piece are connected with each other in the axial direction to form a series of compression cavities for compressing fluid. At the separation position, the movable vortex piece and the fixed vortex piece are axially separated. The main bearing pedestal is suitable for supporting the compression mechanism. The backpressure cavity is formed between the movable vortex piece and the main bearing pedestal, communicates with at least one compression cavity through a communicating passageway arranged in the movable vortex piece or the fixed vortex piece, and is suitable for exerting backpressure on the movable vortex piece so as to press the movable vortex piece towards the connection position in an inclined manner. The first sealing device is arranged between the backpressure cavity and the gas suction area of the compression mechanism and can keep being sealed when the movable vortex piece axially moves. According to the scroll compressor, efficiency can be improved, and the power consumption can be lowered.