The effects of nine nano metal oxides,including Co₃O₄，Fe₂O₃，Bi₂O₃，CuO，PbO，Al₂O₃，TiO₂,NiO and PbO/CuO,on thermal decomposition of HMX were investigated by PDSC,TG-DTG and iso-TG. The results show that the decomposition of HMX in solid phase before melting is advanced by the metal oxides,especially PbO,Al₂O₃ and TiO₂,and the endothermic melting peak of HMX mixed with PbO and Al₂O₃ even disappear entirely,owing to the compensation of exothermic decomposition in solid phase at pressure. Thermal decomposition of HMX in liquid phase at high pressure of 3 MPa is catalyzed by PbO,but not affected by Al₂O₃ and TiO₂. The results of TG-DTG at lower heating rates and iso-TG under HMX melting temperature are in agreement with those of DSC in solid decomposition at ambient pressure. These results are advantageous to the identification of the different effects of nano and normal metal oxides. The catalytic decomposition of HMX by nano and normal metal oxides,including CuO,PbO,Al₂O₃ and TiO₂,were also characterized by the kinetic parameters obtained from isothermal and non-isothermal TG. The kinetic parameters obtained from isothermal TG are in agreement with those from non-isothermal. The catalytic effects characterized by means of kinetic parameters consist also with those by DSC and TG-DTG. The decrements of E_a values of the decomposition of HMX with three nano materials,except CuO,are more than that of those with normal materials.