The invention relates to a novel circulation experiment water tank composed of a U-shaped elbow, wing-shaped flow deflectors, a bolt, a flange, steel wire nets, a straight tube, a cambered tapered tube, a minor-diameter straight tube, a U-shaped water tank body and a long tapered tube. The whole water tank is made of organic glass, and is high in transparency and mechanical strength, light and easy to machine. The wing-shaped flow deflectors are small in resistance and good in diversion feature, and the fluid flow speed is effectively controlled. The straight tube and the cambered tapered tube are connected through the bolt and the flange, and are convenient to dismount. The steel wire nets are installed in the straight tube section, a water flow vortex flowing from the U-shaped elbow is divided into small vortexes, the impact to the water tank is reduced, and the water flow tends to be straight. The long tapered tube effectively prevents an inner bounding layer of the long tapered tube from disengaging. The cambered tapered tube is in a streamline shape and effectively prevents a boundary layer from disengaging, the two ends of the cambered tapered tube are connected through the flange, and the cambered tapered tube is convenient to install and easy to replace. The novel circulation experiment water tank is good in adjusting performance, stable in operation, convenient to manufacture, even in internal fluid flowing speed and simple in structure, brings great convenience to the actual application, and can be widely applied to indoor hydraulics experiments.