Late Mesozoic volcanic activities were divided two periods in Songliao Basin，which constitute Huoshiling and Yingcheng Formation，respectively. The ages of volcanic rocks show two peak values that are 150 Ma and 110 Ma. The volcanoes erupted most intensively in Yingcheng Formation，lasting a long time. There were always volcanisms in Late Mesozoic，while the source rocks of Huoshiling and Shahezi Formations were generating hydrocarbons. Volcanism efficiently enhanced the maturity. It is advantaged for gas pools that the volcanoes erupted before hydrocarbon accumulating，because volcanisms can make migration pathway and volcanic rocks are good reservoirs. There are hydrothermal fluids such as calcite，quartz and magma deposits in volcanic fractures. The KAr age of magma deposits in trachyte fractures is 7298 Ma，which is important for volcanic reservoirs reconstructed，gas migration and CO2 accumulating.
Songliao Basin，Volcanic activity，Hydrocarbongeneration history，Accumulation history，Hydrothermal fluid