In order to study the effects of the star-shaped liner of differently half wedges（15°，25°，35°，45°，55°，67.5°） on jet formation,the LS-DYNA software was used to perform numerical simulation on the process that a structure of the new star-shaped liner forms jet,analyzing the forming process and the effects on forming and jet velocity of the differently half wedges of star shaped liners. Results show that the velocity of second-gathering jet which the star shaped liner forms increases by 33％,compared with the initial jet. The half wedges are suitable for 20°~35°. The penetration performance of jet is better when the number of wedge is 3.