Simulation of FEM based grinding process has a lot of advantages in comparison with analytical models. In this paper, firstly, a simulation model of single grit high speed grinding for DIN-41Cr4 and Ti6Al4V by commercial software DEFORM 3D has been described. And then, grinding experiments and microscope observations of the single grit high speed scratch tests on both materials have been carried out. The end results show that the wheel velocity has a positive influence on the strain rate. Additionally, the temperature lag effect will be much more significant under high-strain-rate process condition. In other words, it is the theoretic element of temperature decrease phenomenon on the wheel-workpiece contact area during high speed grinding. Furthermore, it is found that the high strain rate also optimizes the chip formation performance, which makes it possible to machine difficult-to-cut materials, titanium alloy for example, with high efficiency.