In order to study the external ballistic characteristics of the uncontrolled rockets with dual pulse motors and the influence of different energy distribution on its characteristics, taking the uncontrolled rockets with dual pulse motors as the background, on the basis of the external ballistic characteristics of the routine solid rocket motor, compile the external ballistic calculation program for the uncontrolled rockets with double pulse motors, according to the parameters, the flight performance parameters such as its range and altitude are calculated through the program, and analyze the characteristics of its external ballistics; the external ballistic characteristics of uncontrolled rockets with double-pulse engines under different energy distribution conditions were analyzed from the aspects of pulse interval time, propellant quality ratio, and thrust ratio. The results show that the energy distribution scheme with reasonable pulse interval time, large propellant quality ratio and small thrust ratio should be selected to improve the range of the uncontrolled rocket with dual pulse motors.