The effect of water exchange purpose and water quality status on frequency of water exchange (FWE) in pond aquaculture was investigated. Through the interview investigation processed in Jiangsu Province between July and August from 2015 to 2018, the information of water exchange came from 57 farmers raising Chinese mitten crab (Eriocheir sinensis) was collected. The five types of primary purpose that drive farmers to make water exchange during that season were:compensating the evaporation (without drainage), avoiding hypoxia, routine farming management, preventing disease and improving water quality, which accounted for 47%, 16%, 11%, 11% and 16%, respectively. Water exchange (with drainage) of 19% of farmer seems unnecessary according to the water quality. It was found that FWE to avoid hypoxia or improve water quality was significantly higher than the other three conditions (P<0. 05). FWE was negatively correlated with the fequency of artificial aeration (r=-0. 177, P<0. 1). 111 water quality samples from 64 common fish ponds were obtained through field monitoring in Suzhou and Yancheng City, and the results show that the average ρ (DO), pH, ρ (TN), ρ (NH4+-N), ρ (TP), ρ (PO43--P), CODMn, ρ (chlorophyll a) were (8. 3±2. 7) mg·L-1, 8. 1±0. 5, (4. 3±2. 2) mg·L-1, (1. 0±1. 0) mg·L-1, (0. 56±0. 56) mg·L-1, (0. 29±0. 37) mg·L-1, (12±5) mg·L-1, (133±12) μg·L-1, respectively, and the average FWE was (0. 87±2. 10) times·month-1. The water quality and FWE varied greatly among different ponds. FWE was negatively correlated with ρ (DO) and pH (P<0. 01), and positively correlated with temperature, ρ (NH4+-N), ρ (TP) and ρ (PO43--P) (P<0. 01). FWE was influenced by both water exchange purpose and water quality status, which could be reduced by strengthening artificial aeration.