The working principle of a commercial fishing casting net is to use the shape and gravity of the net to cover the fish and catch the fish. When the user throws the mesh toward the water, it quickly opens up to form a shape similar to a funnel. In the process of escaping, the fish will be restricted by the shape and tension of the net and become trapped in the net. At this time, the user can change the tension and position of the mesh by pulling the rigging, further controlling the capture effect. Finally, the user pulls the net back into his hand, pours the fish out, and completes the catching process