The invention discloses a net floating method. The net floating method includes that 1), a net floats in a horizontal state: stainless steel balls in an inner tube of a T-shaped drainage valve are positioned in the center of the inner tube, and water in a buoyancy tube flows into the inner tube of the T-shaped drainage valve via two U-shaped PE (polyethylene) hoses connected with metal drop tubes, and is sequentially drained out of the T-shaped drainage valve and the buoyancy tube via inner drainage holes in the inner tube, so that the transverse buoyancy tube ascends to drive a net top, a net enclosure and a net bottom of the net to float; 2), the net floats in a non-horizontal state: the stainless steel balls in the T-shaped drainage valve automatically roll to a lower side of the inner tube of the T-shaped drainage valve and plug an orifice of the U-shaped PE hose on the lower side of the inner tube, and under the effect of air pressure, the water is sequentially drained out of the T-shaped drainage valve and the buoyancy tube via the U-shaped PE hose which is arranged on the other side of the inner tube and is connected with the inner tube of the T-shaped drainage valve, so that the transverse buoyancy tube ascends to drive the net top, the net enclosure and the net bottom of the net to float. The net floating method has the advantages that the net can completely float on a water surface, so that the fishing efficiency can be improved, and maintenance on the net can be facilitated.