The invention discloses a construction method of bridge seamless type expansion joint. The construction method of the bridge seamless type expansion joint includes the steps of embedding a sealing strip in the seam portion of the expansion joint, pouring melted 502 elastic-plastic bodies, placing a cross-seam aluminum sheet well, paving various high molecular polymers which fit in with the American society for testing material (ASTM) standard layer by layer, wherein the various high molecular polymers are mixed materials of the 502 elastic-plastic bodies and granite of a corresponding grade, finally using granitic plaster as a surface wearing layer, and the bridge seamless type expansion joint is achieved. The construction method of the bridge seamless type expansion joint has the advantages of satisfying stretch and displacement of an upper portion structure of the bridge, guaranteeing that cars run stably, improving riding comfort, and being strong in elastic restoring force, capable of resisting the high and low temperature, good in plasticity, extensibility, durability, waterproof performance and adhesion performance, long in service life, convenient to install, flexible in installation, rapid in traffic openness and the like. In addition, the construction method of the bridge seamless type expansion joint further has the advantage that the extensible displacement is from 20mm to 50 mm.