Through the determination test for the quantity of gas adsorption and desorption under different temperature conditions, the law of influence of the temperature change on the adsorption and desorption of coal and methane in constant pressure condition was researched. The paradoxical law highly emphasizes that the increase of gas desorption quantity due to temperature rise and part of water adsorbing coal under the effect of high pressure water together affect the quantity of gas adsorption and desorption. In the end, we can obtain the law of desorption seepage of the coal seam gas when the coal was placed under different water contents and different temperature. Making use of the adsorption and desorption experiment system of the coal under constant pressure, the temperature control module was added to the osmoscope, thus, the desorption quantity of the coal sample in different temperature and high pressure water was measured. The result shows that, when the adsorption tank is under the same pressure, desorption quantity of the coal will increase with the temperature; if the same coal sample adsorbs twice, the adsorption quantity is bigger than the former. When it is affected by high pressure water, the adsorption rate of the coal to the gas will reduce. If the same coal sample experiences high pressure water twice, the water quantity injected in the second time is larger; and the adsorption and desorption quantity is different, the second one is a little larger than the first one. The initial temperature is also higher when it begins to desorb. When the coal is affected by high pressure water, the water adsorbed influences the gas desorption and seepage. (C) 2010 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of China Academy of Safety Science and Technology, China University of Mining and Technology(Beijing), McGill University and University of Wollongong.