The precision of Liner is a major factor impacting the depth of penetration of armor-penetrating warhead. By theoretical analysis, the precision of Liner's impact on jet performance was research, and the ANSYS/LS_DYNA software was used to build liner's model with different machining error in the same time. By a series of numerical simulations, the results show that the existence of liner processing error would impact the jet performance, and with liner's processing error increasing, the penetration power declines, providing reference for the penetration depth problem of armor-penetrating warhead.