Combustion process and characteristics of solid waste have been investigated in a laboratory scale fluidized bed combustor(FBC). Evaporation of water, devolatilization, and char combustion are typical combustion process of solid fuel. For specifying these process to the solid waste, thermogravimetric analysis (TGA) is performed with proximate, ultimate and calorimetric analysis. The laboratory scale fluidized bed combustor is used for investigating combustion characteristics of the various kind of solid waste in a real combustion environment. Wood, sewage sludge, paper sludge and refuse derived fuel (RDF) are used for the test samples. Concentrations of CO2, CO and O2 in the flue gas are measured for various experimental parameters such as water contents in the waste, particle size, bed temperature of FBC, mass flow rate of fluidizing air and oxygen concentration in the fluidizing air. Carbon conversion rates are derived from the experimental data for each cases. From the experiments, relatively clear boundary points between devolatilization and char combustion are observed for the cases of wood, while those are not clearly specified in the other kinds of solid waste, which means the two processes are superposed. Devolatilization process is influenced by bed temperature and particle size, while the flow rate of air and oxygen concentration in the fluidizing air have influence on the char combustion process. Water content is related to both of the process.