The compressor cylinder is rotated by the center of the crankshaft centerline under the support of the rolling bearings at both ends. The inner wall of the cylinder casing, the top surface of the piston and the peripheral wall of the cylinder constitute the working element volume of the compressor. The intake port and the exhaust port are arranged on both sides of the cylinder shell according to the position determined by the volume ratio of the compressor. Driven by the crankshaft, this working volume is followed by a rotary motion. When the working volume communicates with the inlet port, the suction process begins. As the rotary motion moves, the working volume expands. When the working volume is disconnected from the suction port, the working volume reaches a maximum and the suction process ends. The working volume forms a closed. As the closed working volume is further rotated, the working volume is also reduced due to the reciprocating motion of the piston, and the gas is compressed. When the closed working volume is in communication with the discharge orifice, the compression process ends and the exhaust process begins. During the further rotation of the working volume, the compressed gas is further discharged until the working volume is disconnected from the discharge orifice, the discharge process ends, and the working volume is zero. The working volume of the star rotor cooling compression structure completes a cycle of suction, compression and discharge. Subsequent working volumes complete the above cycle in sequence, except that they lag behind a fixed phase angle. As the crankshaft rotates, each working volume sequentially completes its respective duty cycle. The body is divided into two parts: the cylinder shell and the oil pool, and the upper space of the oil pool doubles as the suction chamber of the machine. The front end cover and the rear end cover are in contact with the rolling bearing, and the annular oil groove of the fitting portion communicates with the oil pool. In operation, the lubricating oil is delivered to the friction pair such as the mechanical seal and the thrust bearing by the action of the "pump oil" of the rolling bearing. There are throttle holes in the oil circuit to control the amount of oil delivered.