The commercial greases for bearing applications should meet the requirements of the severe conditions of use (high load, low friction and low noise etc.). A kind of overbased calcium sulfonate complex greases was evaluated using an UMT-II friction tester, the commercial lithium greases as reference. The morphologies of the worn surfaces were observed using a scanning electron microscope (SEM). The results show that the overbased calcium sulfonate complex greases have stable friction coefficients as low as 0.090-0.094. At the same time, the overbased calcium sulfonate complex greases exhibited higher wear resistance than that of commercial lithium greases.