Abstract: In order to study the influence of the process parameters including cutting current, cutting speed, workpiece thickness and effective heating radius on the arc cutting quality of low alloy steel, a sensitivity analysis model of arc cutting parameters based on probability system of ANSYS was established. The 2Cr13 was chosen as subject to study, arc cutting process was simulated by applying moving gauss heat source model, and the variation rule of the workpiece temperature and stress field along with different parameters were studied. The sensitivity of the temperature and stress field to different parameters was analyzed by using the response surface methodology. The analysis result shows that the cutting quality is much more sensitive to cutting current and speed compared to the workpiece thickness and effective heating radius. Cutting current and workpiece thickness have positive impact on the temperature field, but cutting speed and effective heating radius have negative impact on the temperature field. These parameters including cutting current, workpiece thickness and effective heating radius have positive impact on stress field, but cutting speed has negative impact. The model is instructive to process design of arc cutting of low alloy steel.