The invention discloses a sampling device of a deep-space asteroid sample collection detector; the structure is characterized in that the device comprises an ejection port, a housing, an ejection ball storage tube, a driving motor, an air valve housing, a piston, a cam, a trigger, a trigger return spring, a pedestal extension bar, a pedestal piston connector, a pedestal, a valve body, a valve core control spring, a valve core, a stopping block, ejection balls, an arch bar, a piston O-shaped sealing ring, and the like. The invention is characterized in that: the driving part controls the starting of the piston; the piston controls the on and off of compressed air by pushing the valve core of the air valve; the ejection balls are ejected out of the pipeline orifice with certain kinetic energy by pushing of the high-pressure air; and the sampling purpose is reached by soil sputtering caused by bumping with the asteroid surface. The invention is a surface trace sample collection device which is small in mass, simple and reliable in structure, and convenient for automatic operation, and overcomes the influence of 'zero-gravity' environment by a diffusion principle.