The stress distribution of the contact area between tool and chip on tool rake face when cutting is studied by finite element method. The friction coefficient and the maximum shear stress are related to the contact condition at the interface. Results show that from tool tip to the separation point of chips, the stress decreases quickly at first, then slowly, and quickly again. It is also found that the cutting depth has great influence on stress distribution, and that there is no slow decrease period of stress curve at cutting depth of 0.13 mm. Meanwhile, cutting speed has limited influence on stress distribution, contact length and chip thickness.