Bicycle shock absorber

The utility model discloses a bicycle shock absorber which is composed of a first air chamber, an oil pressure chamber, a first piston and a sliding rod and further comprises a control assembly and a fine adjustment assembly, the first piston divides the oil pressure chamber into a first oil chamber and a second oil chamber, and a flow channel is formed in the first piston. The first oil chamber and the second oil chamber can be communicated through the flow channel, the flow channel comprises a first through hole and a second through hole, the first through hole is communicated with the second through hole, the sliding rod is inserted into the first through hole in a sliding mode, an adjusting piece is arranged at the end of the sliding rod, a first protruding block is arranged at the tail end of the sliding rod, and the adjusting piece is connected with the first protruding block. The sliding rod is controlled by the control assembly and the fine adjustment assembly, the axial displacement position of the s