The effects of eight nitrogen treatments on yield per unit area,vitamin C content,soluble sugar content,soluble solid content and nitrate content were studied by principal component analysis and cluster analysis with cu-cumber variety ’jinchun 3’ as the experimental material.The results showed that there were significant differences and correlations among the indicators among different nitrogen application treatments,and the effect of nitrogen application on yield and quality could not be evaluated objectively and comprehensively according to the situation of single index or simple index combination.Principal component analysis（PCA） was used to convert six indexes into two principal components,representing 88.139% of the original index data.Through comprehensive analysis and evaluation,the principal component analysis score of N₅ treatment was 15.504,which owns the highest comprehensive score.The results of principal component analysis and cluster analysis were used to fit the comprehensive evaluation score and nitrogen application level.The optimal nitrogen application rate was 19.12 kg/667 m².