The invention discloses an underwater multi-dimensional automatic water sample collecting device. The underwater multi-dimensional automatic water sample collecting device comprises a water sample collector, a three-way valve, a water storage device and a controller; the water sample collector comprises a sampling tube; the sampling tube comprises an outer tube and an inner tube; the inner tube isconnected with the side wall of the outer tube; the inner tube is a hose; a through hole is formed in the side wall of the outer tube; the water storage device comprises a sampling bottle pull rod, asampling bottle and a sampling beaker; the sampling bottle pull rod is connected with at least two sampling bottles; the sampling bottles adopts a volumetric variable type and are connected with theinner tube; the sampling bottles change the internal capacity under the motion of the sampling bottle pull rod; the sampling bottles collect water samples through the inner tube or collect water samples through the sampling beaker, and the water samples with three dimensions can be collected simultaneously, so that multi-dimensional sampling is realized and the effectiveness and the representativeness of sampling are greatly improved; and the process technology is simple and convenient to operate.