One combined wetland system was used in aquaculture wastewater purification of the lake pond, in order to achieve water recycling utilization and reduce the pollution of the surrounding water environment. The combined wetland system was composed of three lotus purification ponds with an area of 2.1 hm² each, one ecological ditch of 1.47 hm²and one constructed wetland of 0.52 hm². The lotus coverage rates of the three purification ponds were respectively 0%, 30%, and 60%. Water chemical indicators were determined by sampling along the way. The results showed that the combination system could effectively reduce the total nitrogen, total phosphorus, ammonia nitrogen, COD and other chemical indexes in the aquaculture wastewater. Total nitrogen and total phosphorus were decreased from 0.76mg/L, 1.3mg/L to 0.4 mg/L, 0.09 mg/L respectively, with the removal rates of 41.5% and 77.5%; ammonia nitrogen and COD were decreased from 0.27mg/L, 42mg/L to 0.06 mg/L, 27 mg/L respectively, with the removal rates being 77.7% and 35%. The research showed that this cycling mode was effective in purifying aquaculture wastewater, realized the goal of "internally circulating and externally sealing" and could effectively alleviate the pollution load of Nansi Lake.