A main body of a suction device comprises a power cavity, a suction cavity and a puncture part and is characterized in that a power cavity opening is closely connected with the upper end of the suction cavity, the puncture part is arranged in the suction cavity, and suction cavity openings are formed below or in the periphery of the puncture part; a piston and a spring are arranged in the power cavity. The inner wall of the power cavity is in sealing and movable connection with the outer wall of the piston, a pressing rod is arranged at one end of the piston, the pressed end of the pressing rod is exposed out of the power cavity, a sealing ring is arranged on the periphery of the piston, the spring is arranged at the sealed upper end or lower end of the piston and drives the piston or the pressing rod of the piston outwards to generate suction force, suction force is transferred to the suction cavity, inner walls of the openings of the suction cavity are bulged upwards, and the inner wall of the suction cavity is in through connection with the inner wall of the power cavity; a sharp needle head or a head is arranged at the puncture part, and a flow guide groove or a flow guide hole are formed in one side of the needle head or the cutting head. The suction device is simple and reasonable in structure, convenient to operate and durable and has high suction force and reliable performance.