A novel silicon-aluminizing diffusion coating was prepared on gamma-TiAl alloy by cold sprayed Al-12Si alloy coating and subsequent heat treatment. The oxidation resistance of silicon-aluminizing diffusion coating was studied at 900 degrees C for 1000 h and 120 cycles. The results showed that the coating decreased the inward oxygen diffusion and thus improved the oxidation resistance of bare alloy effectively. The microstructure evolution of the diffusion coating was investigated. Possible mechanisms related to the oxidation and elements diffusion behavior were also discussed. (C) 2015 Elsevier B.V. All rights reserved.