Abstract: When the seismic wave propagates in the underground media, the seismic wave energy will show a certain degree of attenuation. The quality factor Q is an important parameter for measuring the absorption and attenuation properties of the underground rock, and is of great significance for describing the lithological characteristics and predicting the oil and gas distribution. In this paper, the Q value analysis technique based on S transformation ratio method for deep seismic reflection data was developed, and the more accurate Q value was obtained. Taking the Shahezi Formation in the Songliao Basin as the main target layer, the authors calculated the Q value of the post-stack deep seismic reflection profile across Well SK-2, and then generated the Q value profile to summarize Q value distribution characteristics of the Shahezi Formation. The Q value distribution characteristics, combined with the logging, stratification and gas anomaly data of Well SK-2, suggest that the Shahezi Formation is a gas reservoir, and this discovery provides a way for the next deep reservoir prediction. This conclusion provides an idea for the further deep reservoir prediction and can serve the deep geological survey project in Northeast China.