Abstract: As a novel pumping scheme, the line focus system applied in the grazing incidence is the on-axis parabola. Using 2D ray-tracing program, the line focus effects with different incidence angle of a Gaussian laser pulse were calculated. As the incidence angle increases from 5° to 7°, the length of the line focus is improved from 6 mm to 12 mm, and the widthes are varied from 150 μm to 40 μm. The results show that the 6.5°~7° incidence is capable of realizing a well line focus with 10 mm×20 μm to satisfy our experiment.