The rock cutting performance and cutter-rock contact behavior of partial-worn cutters are investigated via scaled rock cutting experiments. The results reveal that the partial-wear of the cutter reduces the normal force, while the tangential force increases. Changes are also observed in the rock breaking mechanism. Although the rock breaking capacity of the partial-worn cutters is not significantly reduced, the increase of volume ratio of the rock powder results in a rise in specific energy, indicating that the energy utilization of the partial-worn cutters is relatively low. In addition, plastic deformation and abrasive wear are observed on the partial-worn cutter sur -face. The changes of motion modes and surface geometry play a key role in the above-mentioned phenomena.