To study the effects of ignition process on interior ballistic performance of a small-size solid rocket motor, the model for interior ballistic calculation including ignition process of small-size solid rocket motor and verification plan were set up. The numerical calculations interior ballistic performance with 1.0 g, 0.8 g, 0.6 g and 0.4 g igniter masses were carried out. The tests of 1.0 g and 0.8 g igniter mass were done. The compute result and test data were basically consistent. The results indicated that: the effect of ignition process on interior ballistic about small-size solid rocket motor is obvious for the small combustion chamber volume. The igniting charge density and pressure peak increase, stable operating time of motor decreases as the igniter mass increases. The 1.0 g igniter mass is estimated by empirical formula, 1.0 g igniter mass brings too high pressure to motor, the value of pressure reaches three times the stable pressure. 0.8 g igniter mass meets ignition reliability and general design requirements, and the maximum pressure is 27.08 MPa, and stable work time is 159 ms, and 0.8 g igniter mass is suggested for the small-size solid rocket motor.