Abstract: This paper studies the spatial distribution of aquaculture areas in Sansha bay and the impact of aquaculture area changes on water quality in the area, so as to provide scientific basis for water quality environmental protection and sustainable development of aquaculture industry in Sansha bay. It carries out the classified extraction and statistics of remote sensing images of Sansha bay in 2007—2019 by cage aquaculture area and algae aquaculture area, and analyzes the dynamic changes of the area and distribution of two kinds of aquaculture. Besides, it predicts the water quality data of Sansha bay in 2019 by time series analysis model, and conducts the correlation analysis between aquaculture and water quality based on the dynamic changes of water quality and aquaculture area from 2007 to 2019. The results show that the area of aquaculture appeared an overall growth trend from 2007 to 2019. Algae aquaculture area increased rapidly from 2007 to 2014, basically covering the whole Sansha bay area, while it remained stable from 2014 to 2019. And cage aquaculture area continued to increase from 2007 to 2019, which gradually expanded to the waters near Dongan island and Dongchongkou. The change trend of water quality and aquaculture area in 2007－2018 is basically the same, so qualitative and quantitative analysis has verified that there is a certain correlation between water quality and aquaculture area in Sansha bay, and it is further verified by water quality prediction in 2019.