Through the model test of the thermal-explosion oxygen-steam underground coal gasification in the approximately horizontal coal seams with short ribs, the changing characteristics of the temperature field in the gasifier with different gasification methods were discussed in this article. The experiment showed that the rising rate for the roof temperature of the coal seams to be gasified during pure oxygen gasification was about 5.47 degrees C/h, with that of the floor at about 2.83 degrees C/h; while during forward oxygen-steam gasification, the high temperature field mainly concentrates around loosening zones arising from thermal explosions, and the highest temperature in the oxidation zone approaches 1,300 degrees C. According to the experimental data, forward oxygen-steam gasification with moving points can obviously improve the temperature conditions in the gasifier. Under the thermal-explosion condition, compared with forward gasification, the average temperature in the gasifier for backward gasification is basically identical with that of the former.