This article studies the sequence stratigraphy and sedimentary facies of the Taizhou Formation in the Hai’an sag in the Subei basin using seismic data, well log data, and assaying data. The Taizhou Formation can be divided into 2 third\|order sequences and 5 system fields. Sequence 1 consists of the member 1 of the Taizhou Formation, sequence 2 consists of the member 2 of the Taizhou Formation. The sequence 1 was deposited during the faulting period of the basin, during the period when the plain of braided delta, the front of braided delta and shore\|shallow lake subfacies were developed. Sequence 2 was deposited during the depression period and the shrinking period of the basin, during this period, the front of braided delta and deep facies were developed. The main source rocks were developed in the middle of the TST sequence 2 which is also good capping formation. The sand body reservoirs of lake 2 delta and fan delta were developed during the later period of the HST sequences 1 and 2, and are the potential areas for oil and gas.