The invention relates to a lid beam pour slurry-proof improved structure including a first ferrule section and a second ferrule section, the first ferrule section and the second ferrule section are combined to form a ferrule for clamping the pier column, The upper surface of the first ferrule section is provided with a first groove, the upper surface of the first ferrule section is further provided with a first slurry discharge port connected with the first groove, the upper surface of the second ferrule section is provided with a second groove, and the upper surface of the second ferrule section is further provided with a second slurry discharge port connected with the second groove. The invention also relates to a construction method of a cover beam casting anti-leakage slurry improvedstructure. The invention not only has simple and reasonable structure, but also can avoid grout leakage and pollution of the pier column caused by pouring the cover beam, is easy to disassemble and assemble, can be used repeatedly, and has wide application prospect.