A solution culture experiment was conducted to investigate the effects of molybdenum (Mo) on yield and quality of two Chinese cabbage cultivars (low nitrate accumulator L18 and high accumulator H96) under different ratios of NO3--N to NH4+-N.The results showed that fresh weight,contents of Mo and nitrate decreased significantly with the decrease of ratio of NO3--N to NH4+-N.Contents of vitamin C,soluble sugar,total free amino acids and soluble protein in Chinese cabbage increased with the decrease of ratio of NO3--N to NH4+-N.Mo application increased the fresh weight of Chinese cabbage under different ratios of NO3--N to NH4+-N.When the ratio of NO3--N to NH4+-N was 100/0 and 50/50,Mo significantly increased fresh weight of Chinese cabbage.Mo application significantly increased the Mo content of Chinese cabbage under different ratios of NO3--N to NH4+-N.Mo application increased the contents of vitamin C,soluble sugar,total free amino acids and soluble proteins (with L18 soluble protein excepted) in Chinese cabbage,especially under single nitrate nutrition.Mo application significantly decreased the nitrate content in Chinese cabbage when the ratio of NO3--N to NH4+-N was 100/0.However,there was an opposite effect when the ratio of NO3--N to NH4+-N was 50/50.There was no significant effect when the ratio of NO3--N to NH4+-N was 10/90.To a certain extent,Mo could coordinate the contradictions of yield and quality of Chinese cabbages under different ratios of NO3--N to NH4+-N.