In this paper, micro-nano scratching experiments were conducted on mono-crystalline silicon wafer to investigate the material removal mechanism of silicon. Two loading methods (increasing-loading and constant-loading) were used. The characteristics of the scratching grooves, and the relationship between the groove size and the load were analyzed by observing the surface torography and measuring the groove. The results show that there are four distinct regimes existed with an increasing scratching load: elastic regime, ductile regime, ductile-brittle regime and brittle regime. The critical load of the transition from ductile to ductile-brittle regime can be considered as 120mN, within which smooth scratching surfaces have been obtained by ductile removal. The scratching load has very significant effects on the groove sizes of the mono-crystal silicon.