Abstract: The sedimentary environment of the source rock in Tanzhuang Formation,Jiyuan Basin has been briefly dis- cussed in this paper.From the view of geochemistry,the abundance of the organic matter is found to be high and the organic carbon content is averagely 4.68%,the high- est value can be up to 11.63%.The type of organic mat- ter mostly belongs toⅡA andⅡB,the transitional type of oil generation and gas generation,and the maturity of the organic matter is between lower and high stage,which has great potential of hydrocarbon generation.