Microthruster is a key for the long-term mission of nanosatellite. Micro rocket array system using solid propellant is treated theoretically and experimentally. Ignition model of energetic material is developed to understand the reaction of propellant in micro tank. It is found that there is suitable particle size of solid propellant and high heat fluence is desired. Two kinds of igniter circuits for Mega-bit microthruster are discussed and the simpler one is fabricated using MEMS technology. Successful heating of resistor in the order of 40μm is established and the reason of unstable ignition is also discussed.