The effect of relative humidity on relative water loss rate and water evaporation strength of spinach,green Chinese cabbage,cucumber and scallion under low temperature(5 ℃) conditions was studied.The results showed that the water evaporation strength of vegetables was closely associated with the specific surface.Different relative humidities also had a great effect on the relative water loss rate,and larger relative humidity resulted in a reduced relative water loss rate by lowering transpiration in vegetables.Moreover,the relative water loss rate of leaf vegetables was more affected by relative humidity.The water evaporation strength of different vegetables was influenced differently by relative humidity;almost no effect on cucumber or spinach was found,while scallion and green Chinese cabbage were both affected by relative humidity.