In high speed metal cutting, the irreversible dislocation motion and multiplication result in the plastic deformation of the metal, and its velocity are proportional to the drag force of the solid. Therefore, the effect of viscosity becomes more and more important in describing the material dynamic behavior. The damping mechanism of dislocation in high speed metal cutting is described from the fluid aspect; a model for high speed machining is established based on fluid mechanics. The velocity distribution, the pressure distribution and the strain rate distribution are calculated by solving the Navier-Stokes equation and energy equation, which provides a new method to study high speed machining. Analytical results show that approximating the behavior of metal cutting by a fluid model during high speed machining is not irrelevant. A speed stagnation point is located at some distance from the tool tip on the tool rake face on which the maximum value of the pressure occurs, with zero speed. Its location influences the life of the tool and the quality of the finished surface. The pressure decreases along the rake face and reaches zero at some point away from the tool tip, which is the point of separation of the chip from the tool. The value of the strain rate exhibits a rapid increase from the tool tip to the free surface corner, and then decreases outwards.