To furtherly improve the penetration capability of explosively formed penetrator(EFP), a type of cone-arc liner which can form long rod-shaped compacted EFP was proposed based on the arc section design of large cone angle liner structure. The difference in collapse process for cone-arc liner and the traditional large cone angle liner as well as arc-cone liner was analyzed. The influences and regulars of cone-arc liner structure parameters (curvature radius, cone angle and wall thickness) on the formation parameters of penetrator, such as EFP velocity, length-diameter ratio and compactness, were calculated and obtained by LS-DYNA simulation software. The range of each parameters of optimum EFP are gained: the curvature radius is 1.1-1.3 times of charge diameter, the cone angle is 155°-160°, and the wall thickness is 0.04-0.046 times of charge diameter. And a kind of cone-arc liner structure that can form EFP with length-diameter ratio as 2 and compactness as 0.88 was designed and obtained.