In a nanoscale friction test, wear of an atomic force microscope (AFM) tip is inevitable. The shape of the worn tip influences the friction force measured. In order to eliminate the influence, nanowear pretreatment should be conducted for the AFM tip. In our study, pretreatment of three kinds of tips, i.e. Si3N4 tip, Si tip and silica colloidal tip, was performed using AFM. The results show that the shape of the tips changes with the increase of sliding distance, which leads to the variety of friction force. Whereas, when the tip gets blunt, the shape of tip tends to become stable and the friction force becomes stable correspondingly. To a certain degree, it reveals that the pretreated tips can be applied to study the friction force of samples.