Abstract:The dissolved oxygen was detected in crab eco culture ponds within 24 hours in the high temperature season between the aquatic plant sparse area and the aquatic plant concentration areas, when it is sunny, windy and rainy. At the same time, the dissolved oxygen was detected between the upwind areas and the downwind areas on the windy day. The results show that the dissolved oxygen is the highest from 14:00 to 16:00, and the lowest from 4:00 to 6:00 within 24 hours. When it is 10:00-16:00 in the high temperature season, the thermal resistance appears between the upper and the lower water in the ponds, so the significant difference shows between the upper and the lower water (P<0.05). The maximum difference is 10.4 mg/L at 14:00. The dissolved oxygen is 0.2-2.5 mg/L in the lower water at 6:00. When it is strong winds, the difference is litter between the upper and the lower water at 14:00, and the dissolved oxygen is 1.2-4.9 mg/L in the lower water at 6:00. When it is rainy, the difference is least between the upper and the lower water, and it is 3.4 mg/L at 14:00. The dissolved oxygen is 0.6-1.0 mg/L in the lower water at 6:00. The dissolved oxygen in the aquatic plant concentration areas is significantly higher than the aquatic sparse area (P<0.05), except it is rainy. When it is windy, the dissolved oxygen in the downwind areas is significantly higher than the upwind areas at 16:00 (P<0.05), but the no significant difference is showed at 6:00 (P>0.05). In conclusion, the aquatic plant is the main producers of the dissolved oxygen in the crab eco culture ponds. The research provides some reference for increasing dissolved oxygen in the crab eco culture ponds.