Main rocket’s rotating speed is an unfavorable influence to sub munitions’ spread, to reduce this unfavorable influence; inclined tails have been designed in this paper. The Least tail installation angle has been selected under the condition that the main rocket flies steady to reduce the rolling moment maximizing the tails produce while flying, so that the main rocket’s balancing rotating speed decreased to least while flying, this make the unfavorable influence drop to the lowest. At the same time, time sequence has been designed for sub munitions’ dispersing. The experiment proves that sub munitions drops＇characters are good under this tail angle and time sequence of 1.5s, controllability of sub munitions drops＇character has been improved, content the sub projectiles inflict causalities efficacy well. There is a certain practical value.