Vapor aluminizing process and microstructure of hollow blade in aero-engine has been researched. The mechanism of the coating has been analyzed. The results show that the depth of the surface coating is 20~60μm

by 30% Al aluminizing powder. And the internal coating of turbine blade is 5~20μm. The depth increases with the extension of the aluminized time. The coating mainly comprises two layers with the same depth. The surface layer is 32%~36% Al

with β-NiAl phase. And the inner layer is 11%~17% Al

with β-NiAl phase

or β+γ' phase

or γ’ phase. There are needles which are arranged disorderly and a small amount of foreign substance in the inner layer. The main reason of high-Al in the coating is the rust of crucible. The crucible has been forced aluminized with high temperature and long time. The blade coating has good microstructure and mechanical properties after been vapor aluminized at 980℃ for 4h

through the assessment of the aero-engine 1000h lasting. The prospect of engineering application for vapor aluminizing process of hollow blade is very good.