The northern area of Santanghu is one of the major coalfields which have been recently ascertained in Xinjiang. The coal bearing stratum is covered with cenozoic sandstone confined aquifer. The cenozoic sandstone confined aquifer is one of the most important sources of water supply during coalfield development process. Based on detailed hydrogeological survey data of coalfield water supply in northern area of Santanghu, the paper propsed the concept of aquifer sandstone index (ASI) and set up the relation between ASI of confined aquifer and water yield of single well. The results show that there is a significant linear correlation between ASI of confined aquifer and water yield of single well. When using ASI to predict water yield of single well, the relative error is generally less than 50% and mean absolute error and average error is 7.59 m3/d and 1.07% respectively.The fitting degree is higher. The relative error is generally less than 15% in suitable well area while the water yield of single well is more than 500 m3/d with very high fitting degree. The result has important practical significance for prediction of water yield of single well of confined aquifer in suitable well area and rational arrangement of groundwater extraction well.