Abstract: In order to achieve the upgrading of lignite and solve the problem of drought and water shortage in main producing area of lignite, the water quality of condensed water with different drying media were carried out with a fixed bed reactor and an inductively coupled plasma mass spectrometry. The gas production rate of coal samples under different drying temperature was also analyzed. The results indicate that two different particle size of coal samples with extended drying time, moisture content of coal sample reduced gradually, and dehydration temperature is higher, the lower the moisture content. Some small molecular compounds in the structure of the coal molecules are partially pyrolysis with the increase of the dehydration temperature, leading to the content of COD in condensate water was produced from dry coal sample with particle size of 6 to 3 mm under the atmosphere of oxygen at 140℃ was 230mg/L. With the increase of the dehydration temperature to 280℃, the content of COD in condensate water of dry coal sample increased rapidly to 37800mg/L. The values of COD, BOD, NH3-N and TON in condensate water was produced from dry coal sample with particle size of 0.5 to 0 mm are slightly larger than 6 ~ 3mm coal samples under the same drying conditions.Four kinds of heavy metal ions in condensate water as the dehydration temperature rises, the amount of precipitation were increased gradually. However, the content of heavy metal ions in the condensate water is much lower than that of the surface water environment quality standard V. When oxygen is used as a drying medium, the CO2 and CO are produced in addition to the decomposition of the coal sample itself, and the other part of CO2 and CO are produced from the weak oxidation reaction of coal samples during the drying process.