Abstract: Three biomass wastes were studied with thermal analyzers. The pyrolysis characteristics were analyzed by using active and passive pyrolysis zone, and pyrolysis index. The pyrolysis kinetics parameters and controlling equations were derived from thermal gravimetric analysis. A general pyrolysis rate equation was deduced. The results show that pyrolysis of agriculture residues is not active in passive pyrolysis zone, but pyrolysis of wood residues is still active. Pyrolysis indexes increase with higher heating rate, which is beneficial to biomass pyrolysis. Pyrolysis of three biomass wastes conforms to two-stage model. Pyrolysis mechanism and kinetic parameters are different within different temperature range. For the same biomass sample, the main factors affecting the reaction rate are reaction kinetics parameters, while heating rate does not change the reaction rate equation but changes the reaction kinetics parameters.