Underground water sampler

The utility model discloses an underground water sampler, and relates to the technical field of underground water engineering, the underground water sampler comprises a support frame, rollers are fixed on two ends of the bottom of the support frame, a sample box is fixed on one side wall of the support frame, a sampling cylinder is arranged in the middle of the support frame, and a cover plate is fixed on the top of the sampling cylinder through a magnet; the cover plate and the top of the sample cylinder are fixed to the rotating shaft through a first steel wire rope and a second steel wire rope, and a cleaning structure is arranged at the end, away from the sample box, of the supporting frame. The cleaning structure is arranged at one end of the supporting frame, after the sampling barrel samples, a cleaning brush is driven by a motor to rotate, the inner wall of the sampling barrel is brushed, manual cleaning is not needed, and the working efficiency is improved, a cover plate is fixed to the top of the sa