Apart from facilitating the development of the potato processing industry and enriching the diets of people， breeding of potato varieties with good nutritional qualities also contributes to the adjustment of the national-wide planting structure. Protein， vitamin C and potassium （K） are important quality traits in potato. In this study， the genetic variation of protein， vitamin C and K and their interaction relationship in 118 potato breeding lines were assessed by cluster analysis and the two-dimensional quadrant method. The variable coefficient of protein， vitamin C and K content were 16.34%， 26.01% and 14.19%， respectively， and the genetic diversity index were 1.9744， 1.9952 and 2.0411， respectively. These indicated a broad genetic basis for protein， vitamin C and K content in this collection. The protein content was extremely significantly positively correlated with the K content in potatoes. The cluster analysis enabled the classification of 118 potato lines into four groups. The lines in groups I and II had lower protein content； the lines in group II had high vitamin C content； the lines in group III had the highest contents of protein and K； the lines in group IV had the highest vitamin C content. Twenty lines showing multiple high nutritional qualities were identified by two-dimensional quadrant analysis. Gained from these results， it is possible to identify potato varieties with high nutrition and suitable for planting in Fujian province of P. R. China. This study might provide useful materials breeding and deciphering the mechanism of elite potato varieties with high nutritional value.