Pressure detection device and system, and shock absorber

The invention relates to a pressure detection device and system, and a shock absorber. The pressure detection device comprises a first sealing structure, a first pressure sensor and a signal conditioning circuit, the first sealing structure can be connected with a first through hole in a sealed mode, and the first through hole is a through hole penetrating through a rod sealing unit of the shock absorber; the first pressure sensor is arranged on the first end surface of the first sealing structure; and a first wire of the first pressure sensor penetrates through the first sealing structure inthe direction from a first end face to a second end face and is coupled with the signal conditioning circuit. When the first sealing structure is connected with the first through hole in a sealed mode, the end face, facing an upper cavity of the shock absorber, of the first sealing structure is a first end face, and the end face, back to the upper cavity of the shock absorber, of the first sealingstructure is a second end