Thermodynamic analysis was carried out for theoretical reaction of hydrogen produced from dimethyl ether (DME) auto-thermal reforming by using the minimum of GIBBS energy. The volume content of various gases were calculated at adiabatic condition as function of air to DME ratio (0.2~0.8), H2O to DME ratio (1~6) and pressure (0.1~0.6MPa). The result proves that the volume content of H2 decrease with the increasing of pressure. With the increasing of the H2O to DME ratio and the O2 to DME ratio the volume of H2 increases first then decreases. With the increasing of the H2O to DME ratio the volume of CH4 and CO decreases, the volume of CO2 increases. The model reliability was verified experimentally on self-designed equipment. The experiments data are closed to simulation results.