In order to develop municipal solid waste(MSW) gasification and melting technology with low emission and high efficiency for developing countries, the optimum conditions of ployethylene plastic gasification were studied.Polyethylene(PE) plastic widely existing in MSW was gasified in a fluidized bed. The study was focused on the characteristics of PE gasification at different excess air ratios(EAR) (0.2—0.8) and temperatures (400—700℃).The highest gasification efficiency reached 72% in the above experiments when temperature was 700℃ and EAR was 0.2,and the low heating value(LHV) of product gas was up to 10000 kJ·m -3 , the yield was 3.1 m3·kg -1 and the conversion efficiency of C was 80%. The conversion efficiency of C could be increased up to about 100% if temperature was maintained at 700℃ and EAR was over 0.4 (or temperature at 600℃, and EAR over 0.8).Then the reaction process and mechanism of PE gasification were proposed by analyzing the characteristics of product gas.