Abstract: In order to clarify the space distribution law and the control factors of the gas content saturation in southern part of Qinshui Basin, the analogical metho d, the interpolation method, the comprehensive analysis method and other method were applied to the study on the No.3 seam and No. 15 seam.The results showed tha t the gas content saturation of No.3 seam would generally be 20.60% to 128.01%, the average saturation would be 70.53% and the variation scope would large.The gas content saturation of No.15 seam would generally be 11.09% to 132.42%, the average saturation would be 59.47% and the distribution would be concentrated.Generally the gas content saturation of No.3 seam would be higher than No. 15 seam.Therefore the southern part of the Qinshui Basin could be divided into three blocks.Among th e three blocks, the block I in the north part of the Yuchi in the study zone would be highest in the gas content saturation.The block I in the north part of the block I a nd the east of the Sitou fault and the west of Fanzhuang would be second high in the gas content saturation and the block in the east part and south part of the study zone would be low in the gas content saturation.The paper pointed out that the gas content saturation and the coal bed methane content would be in a positive related r elationship, the gas content saturation and the seam deposit depth would be in a negative related relationship. The hydrological conditions of the seam thickness, coal「 ank and seam deposit location would have a certain influence to the gas content saturation.