An embodiment of the invention discloses a method of integrally manufacturing a trash rack plate of a drainage chamber. The method comprises the following steps that (1) the size of a water outlet ofthe drainage chamber is measured, a tile with arc-shaped structures on the top edge and the bottom edge is selected, and the size of the tile is larger than that of the water outlet of the drainage chamber; (2) the opening position is determined, specifically, the reserved position of the trash rack plate is determined according to the size of the water outlet of the drainage chamber; (3) cuttingis conducted, specifically, the tile is cut according to the reserved position, a reserved hole is formed, and at least two breakage points are reserved on the edge which needs to be bent and is located in the reserved hole in the rolling process; (4) the trash rack plate is installed, specifically, the trash rack plate is installed in the reserved hole, the trash rack plate and the tile are welded, and the welding positions are the positions of the breakage points; and (5) rolling is conducted, specifically, the tile where the trash rack plate is installed is rolled, so that the trash rack plate of the drainage chamber is obtained. By the adoption of the method, the frequency of rolling of the tile is effectively reduced, and the rolling quality is improved. Meanwhile, the difficulty andthe workload in the process of welding of the trash rack plate and the tile are reduced, the working efficiency is improved, and the cost is saved.