In order to evaluate the propulsion performance of MEMS (Micro Electro Mechanical Systems) solid propellant thruster array, accurate measurement of unit micro-impulse is particularly important. Based on the traditional ballistic pendulum, as well as considering the relationship between the thrust and the impact of the gas jet, an indirect micro-impulse measuring device was designed. It was successfully used in the measurement of 6mm×6mm (integration density is 36/cm2) MEMS solid propellant thruster array. The results show that the unknown micro-impulse is 2.5442×10-4N·s under typical experimental datum, and the measurement accuracy meets the requirement of ballistic pendulum system in which the relative error is below 5%. The average impulse of 8test units is 2.5574×10-4 N·s with small relative deviation and good reproducibility.