Combined with the latest research progress of gravity flow deposition theory at home and abroad，the sedimentary characteristics，formation mechanism and sedimentary models of the gravity flow sand bodies in the Sha3 member of the slope zone in the southern part of the Bonan Sag in Zhanhua Depression were studied systematically using core data，granular analysis，well logging and other information. The research shows that the gravity flow sand bodies mainly include sliding-slump sand bodies，sandy debris flow sand bodies and turbidite sand bodies based on the rheological characteristics and sediment support mechanism in the study area. The sliding-slump sand bodies distribute dispersedly with abundant synsedimentary deformation structures；the sandy debris flow sand bodies are thick and massive with floating mud gravel inside；the turbidite sand bodies area mainly composed of thin layer sand and mudstone with the coarsening upward succession. The sliding-slumping sand bodies are mainly distributed at the upper part of the slope zone；the channel microfacies dominated by sandy debris flow sand bodies and the channel edge microfacies dominated by turbidite sand bodies develop at the middle and lower part of the slope zone，which presents a belt-like distribution. The channel end microfacies dominated by sandy debris flow sand bodies and the interchannel and the sheet sands microfacies dominated by turbidity sand bodies distribute in the sag zone，which presents a fan-like distribution. According to the distribution law and formation mechanism of gravity flow sand bodies in the study area，the sedimentary model of gravity flow sand bodies in the slope zone of rifted lacustrine basin was established under a multi-source，mud-rich and sand-less condition.