The thermal decomposition behaviours of the outer material of the high-pressure fully wrapped composite hydrogen storage tank were studied in cone calorimeter with a piloted ignition at various heat fluxes. The characteristic parameters, such as ignition time, mass loss rate, heat release rate and effective heat of combustion, were measured. In particular, the correlations of the ignition temperature, thermal response parameter, the heat of gasification and the heat of combustion were derived. The composite material satisfies the thermally thick model. The only one peak appears on the curve of MLR, HRR or EHC at the heat fluxes below or equal to 30 kW m(-2), while one main peak and multiple small peaks appear at the heat fluxes greater than 30 kW m(-2).