Abstract: Through monitoring the pH and EC (electrical conductivity), three renewal frequenciesF10,F20,F30and their influences on the yield and quality of Chinese cabbage in soilless culture were conducted in this research: The results showed that no significant variation existed among F30, F20 and F10 treatments in terms of leaf number and plant height, stem diameter, shoot fresh weight, root fresh weight, dry weight and other morphological characters as well as contents of chlorophyll. Compared with F10, vitamin C content of F20 and F30 treatments increased, and content of nitrate decreased significantly, and the effect of F30 treatment was better than F20 treatment.