Abstract: Five non-heading Chinese cabbage inbred lines were used as parents, and twenty cross combinations were made according to Griffing complete diallel cross design, then the combining ability of main nutritional quality traits in five inbred lines and twenty combinations was analyzed, in order to provide reference for high quality breeding by utilization of heterosis.The results showed that there was no significant difference among the block of six nutritional quality traits, while the variance among genotypes was extremely significant.The general combining ability（GCA）,special combining ability（SCA） and reciprocal effect of six nutritional quality traits were different significantly.It indicated that these traits were affected by additive effect, non-additive effect and reciprocal effect.The combining ability of inbred lines tested was varied in different traits, the GCA relative value of inbred line P4 was higher than those of other lines in four traits including dry matter, vitamin C,protein and soluble sugar.Inbred line P4 was well for high nutritional quality breeding.The SCA relative values of the same trait between different combinations were significantly different, while the SCA relative values of different traits in the same combination were also significantly different.Combination P5×P3 had higher SCA relative values in four nutritional quality traits including dry matter, vitamin C,total acid and crude fiber.In summary, the selection of female parent must be valued in producing cross combination.There was no significant correlation between specific combining ability of combination and general combining ability of inbred line.Therefore, to obtain combination with high nutritional quality and high specific combining ability, making as many test crosses as possible was necessary.