Water evaporation over Lake Poyang in China was studied in August 2013. Actual water evaporation was measured using a special system, showing strong turbulence and daily variations controlled by wind speed. The average water evaporation was higher than pan evaporation, with the ratio decreasing over time. Daily water evaporation was linked to wind speed and humidity, while pan evaporation was affected by radiation, temperature, and humidity due to its small size compared to the lake.