The invention discloses a sampler for underground water quality investigation. The sampler comprises a connecting pipe head, a sampling hose, a sampling pump, a supporting vertical seat, a movable base, movable wheels, a liquid collecting box, a sampling switch, a supporting rod, a protective cover, a square head bolt, a liquid outlet pipe, an anti-blocking sinking type cleaning net cylinder structure, a rotatable anti-confusion sample collecting bottle structure and a liftable hose storage machine. Through the arrangement of the anti-blocking net cylinder, a dismounting disc, a suction pipe and a butt joint pipe head, the blocking can be avoided during underground sampling, impurities can be filtered, the impurities can be prevented from being sucked out, and the sampling cleanliness is guaranteed. By arranging the balancing weight and the rust-proof cover, the sinking effect can be achieved, and it is guaranteed that sampling work is conducted smoothly. By arranging the sampling bottle, a rotating disc, a rotating shaft, a deep groove ball bearing and a fixed base, the position of the sampling bottle can be rotated, and sampling work can be conducted conveniently.