Research have been made on the type of sedimentary facies, the sedimentary features, the model of sedimentary facies and the sedimentary evolution of Sanjianfang and Qiketai formation of middle Jurassic in north of Taibei, Tuha basin, and the research result shows that two types of sedimentary facies—braided stream delta facies and lake facies, and five types of compositional models of mirco-facies develops in Sanjianfang and Qiketai formation. The sedimentary system of braided stream delta mainly develops on offshore slope belts of lake in north depression, and composes the following five micro-facies: branched channel, debouchure ban, reef sand, waterfront sand and mud flat. So that delta-offshore and shallow lake sedimentary system with a positive cycle is available. In the paper, the author discusses the relationship between distribution of sedimentary facies belts and gathering of oil and gas, and concludes that the micro-facies of branched channel, debouchure ban, reef sand is the better gathering sites of oil and gas in the research area which points out the direction of exploration and exploitation in the future.