Plasma gasification is widely applied because of its clean syngas production performance and high chemical reactivity accelerated by the free radicals produced by plasma. In the present study, the plasma gasification of four kinds of coal with various conditions of O-2/fuel ratio, steam/fuel ratio, and coal particle sizes was performed by using a 2 kW microwave plasma unit. Nitrogen was used as a plasma forming gas. Gasification was conducted with an O-2/fuel ratio of 0-1.3, a steam/fuel ratio of 0-1.5, and a coal particle size of 45-150 mu m. With an increasing O-2/fuel ratio, the H-2 composition in the syngas decreased while the CO2 content increased. The CO composition increased until reaching an O-2/fuel ratio of approximately 0.6, depending on the coal type, and decreased thereafter. CH4 was not observed in a syngas, which is typical of high temperature plasma gasification. The H-2 and CO2 contents tend to increase, and the CO content in the product gas decreased with increasing steam/fuel ratio. The syngas composition produced from plasma gasification at same conditions is affected by the physicochemical properties of coals. The Shenhua coal shows highest H-2 production of other coals by plasma gasification. Gasification of coal with high moisture content generates high CO2 composition in the syngas.