To understand the deformation and removal mechanism of material on nmae-scale and at ultralow loads, a systemic study on AFM micro/nanc-machining on single crystal silicon is conducted. The results indicate that AFM rmne-machining has a precisely dimensional controliahility and a good surface quality on rmnometer scale.A SEM is adopted to observe nanc-machined region and chips, the results indicate that the material removal mechanisms change with the applied normal load.An XPS is used to analyze the changes of chemical composition irtside and outside the nanc-machined region respectivaly. The nano-indentation which is conducted with the same AFM diamond lip on the machined region shows a big discrepancy compared with that on the macro-scale. The calculated results show higher nano-hardness and elastic modulus than normal values. This phertornen0n can be regarded as the indentation size effect (ISE).