The invention relates to a chromizing timing chain for an engine, which can replace a belt and a gear, also has the advantages of being heat-resistant, wear-resistant, oxidation-resistant, corrosion-resistant and long in service life, and can meet the requirements of high rotation speed, variable load and high impact of the engine. A chain pin shaft is a GCr15 pin shaft, and a surface layer of the GCr15 pin shaft is a metallic cementation layer; the chromizing timing chain comprises an engine timing chain, and the chain pin shaft in the engine timing chain is the GCr15 pin shaft; the surface layer of the GCr15 pin shaft is the metallic cementation layer; a chain plate in the engine timing chain is tooth-shaped and the tooth-shaped meshing arc surface is a concave-convex tooth meshing surface. The chromizing timing chain has the advantages that 1 the pin shaft is prepared from a GCr15 material, and the GCr15 pin shaft is subjected to chemical thermal treatment by adopting a metallic cementation, so that the chain pin shaft has the advantages of being heat-resistant, wear-resistant and oxidation-resistant; 2 the shearing strength of the pin shaft is increased; 3 the noise is greatly reduced fundamentally, the design target of a silent chain is realized, and the service life of the chain is greatly prolonged.