This paper deals with the effect of adding rare earth (RE) in 880 degreesC drip-feed carburising atmosphere on the microstructure and microhardness profiles in carburised layer, carbon potential and kinetics of weight gain of 20CrMnTi steel. The results show that the incorporation of RE increases the carbon potential, flux of carbon and layer thickness. It is also found that compared with 880 degreesC carburising, a good microstructure with a super fine martensite and less residual austenite were formed based on a lot of dispersed granular carbide precipitates in the surface layer during RE carburising, which resulted in a remarkable increase in microhardness.