The synthesis of ammonia has been studied in methane-nitrogen plasmas using a micro-gap discharge under an environmentally friendly condition. The effects of some parameters such as the specific input energy, the discharge gap, the volume ratio of CH(4)/N(2), the residence time, and the gas temperature on the yield of NH(3) and conversion rate of CH(4) are discussed in the paper. The results show that the highest yield of NH(3) is 8000 ppm for a residence time of 1.6 s. In addition, the yield and generating rate of H(2) are 9.1% (v/v) and 1879.8 mu mol/min, respectively. Therefore, the micro-gap discharge is an efficient method for NH(3) synthesis and H(2) generation from CH(4.)