<p>Fault steep slope zone is an important oil and gas exploration area in sedimentary basin. Taking Wenchang Formation of the Enping 17 Sag steep slope zone in the Zhujiang River Mouth Basin as the research object, this study primarily utilized 3D seismic data as well as drilling and logging data from Well 3-1. Through sequence boundary identification and seismic facies analysis, the distribution characteristics and controlling factors of the fan in the steep slope zone of the Wenchang Formation in Enping 17 Sag are deeply studied. Two second-order sequence boundaries (T80, Tg) and five third-order sequence boundaries (T81, T82, T83, T84, T85) have been identified in the Wenchang Formation. The study concludes that the Wenchang Formation develops fan delta facies in the northern steep slope zone, with a semi-deep lake facies in the middle and a braided river delta facies in the southern region. The fan is mainly distributed at the intersection of two faults, and its migration is affected by the strike-slip nature of the north-south (NS) fault, gradually moving towards the southeast (SE) direction. In the current landform, the fan from Member 6 to Member 1 of the Wenchang Formation exhibit a trend of migration towards the northwest (NW) direction. The formation and distribution of the fan is influenced by various factors, including structure, provenance, paleoclimate, and lake level changes. Among these, tectonic factors play a dominant role in determining the scale and distribution of the fan. The parent rock dominated by granite determines the sediment composition, and the warm and humid climate provides sufficient detrital material for the rapidly accumulating fan near the source. The lake level changes affect the thickness and extension range of the fan.</p>