Abstract: The deepwater gas fields in the eastern South China Sea are mainly deposited by gravity flow, with few drilling wells, complex reservoirs, and multi-stage overlapping development of sand bodies. Traditional seismic interpretation has low accuracy and strong ambiguity, which cannot meet the requirements for fine reservoir research in the gas field development and production stage, resulting in unclear understanding of the fine division, comparison, and distribution characteristics of sand bodies. How to improve the precision and reliability of seismic interpretation results, and carry out reservoir fine interpretation, is one of the key issues in current development and production. This article applies global optimization seismic automatic interpretation technology to establish a global isochronous stratigraphic interpretation model for the first time, providing an effective means for obtaining high-precision isochronous stratigraphic slices. Based on this, seismic geological integrated interpretation is carried out, providing a strong basis for the fine division of sand body stages under the condition of few wells in deepwater gas fields, and clarifying the distribution characteristics and variation laws of sand bodies in different sedimentary periods. This technology provides a new implementation method for fine seismic interpretation under complex sedimentary conditions, and has high practicality and promotion value.