A compressor and a refrigeration system are provided. The compressor has a shell, an air cylinder assembly and a pressure relief device. The shell has a containing cavity. The air cylinder assembly is disposed in the containing cavity, and has an air suction cavity and a pressure relief channel. The pressure relief channel communicates with the air suction cavity and the containing cavity, and has a pressure relief opening. The pressure relief device is connected with the air cylinder assembly. The pressure relief device moves in the axis direction of the pressure relief channel, so as to open or close the pressure relief opening.