The invention discloses a river basin water-based environment management decision support system comprising a hydrology and water quality information collection module, a video information collection module, a data transmission module, a hydrology and water quality information management system, a monitoring center, a data processing module, an expert assessment module, a 3D effect generation module, a display, and a man-machine operation module. Water-based environmental elements of a river basin can be detected in real time, the water-based environment can be scientifically evaluated, and therefore, a feasible decision scheme can be put forward. Moreover, the situation of the river basin water-based environment can be shown in front of the staff through the 3D effect generation module, so that the staff can observe and feel the change in the water-based environment in an immersive way. The reliability of river basin water-based environment management decision is further improved.