Eleven grain quality traits of 76 cultivars (lines) from Yunnan Provincial were analysed using the method of phenotypic principal component and cluster analysis. The results indicated that: (1) The mean of amylose content and milled rice rate met 1 and 3 level of edible rice grain quality standard, respectively. And those of brown rice rate, transparency, alkali digested value and gel consistency fit 2 level of that standard.Whereas those of other traits were below 3 level. Among variation coefficients of the grain quality traits, those of brown rice rate and alkali digested value were lowest,,while that of chalky area was highest, and the follow was chalky rice rate . (2) There existed complex relationship among rice grain quality traits. (3) The cumulative contribution rate of milled rice rate, chalky rice rate and chalky area to grain quality was 49.6% among six principal component factors affecting grain quality traits. (4) 76 cultivars (lines) could be classified into four groups according to genetic distance. There were 52 cultivars in No.1 groups, indicating near genetic distance and narrow genetic basis among most of the cultivars. In order to improve the grain quality of Yunnan japonica cultivars, chalky rice rate and chalky area should be reduced while milled rice rate and head rice rate are necessary increased .At the same time, it is also important to broaden the genetic basis in japonica rice breeding.