Deep-water channel is getting more attention as one of the important reservoirs for oil and gas exploration in the northern South China Sea with the discovery of Central Cannon gas field group. This paper describes the features of the Miocene channel system in the south of Qiongdongnan Basin and analyzes the channel evolution based on 3D seismic data and the technologies of strata slice and seismic attribute extraction. Based on extending direction, horizontal distribution and cutting shape of the channel, the evolution of Miocene channel system is divided into three stages: confined channel system with middle-high amplitude and V-shape cutting down developed in the early-middle period of the Early Miocene, extending in NE-SW direction; straight channel system with V-shape or U-shape developed widely in the late of the Early Miocene to Middle Miocene, extending in SE-NW direction; in the Late Miocene, great channel with U-shape cutting down developed locally in the northeast of the study area, extending in SE-NW direction. The development of Miocene channel system was affected by paleogeomorphology and sea level change. In the Early Miocene, confined channel system developed in narrow and low terrains around west part of Xisha carbonate platform. In the Middle Miocene, straight platform slope channels developed with relative sea level dropping. In the Late Miocene, only a few great channels developed with relative sea level fast-rising.