Abstract: In order to breed the tartary buckwheat（Fagopyrum tataricum） varieties with thin-shell and large-grain and excavate the candidate genes for the grain shell rate-related traits, this research analyzed the genetic variation and quantitative trait locus（QTL） for grain shell rate, hundred grain weight, hundred kernel weight and hundred grain shell weight of the recombinant inbred lines（RILs） population derived from the cross of ‘Xiaomiqiao’（rice type） and ‘Jinqiaomai 2’（non-rice type） under two growing seasons. The four grain shell rate-related traits of non-rice type parent and lines were significantly higher than those of rice type parents and lines. The coefficient of variation of the four grain shell rate-related traits in rice type lines and non-rice type lines ranged from 9.01% to 15.66% and 8.21% to 14.04%, respectively. The grain shell rate had an extremely significant positive correlation with hundred grain weight, hundred kernel weight and hundred grain shell weight. Cluster analysis showed that rice type lines R160, R198, R199 and R46 and non-rice type lines R102, R120, R125, R142, R157 and R178 with lower grain shell rate and higher hundred grain weight under the two growing seasons, which could be used as candidate materials for breeding tartary buckwheat varieties with thin-shell and large-grain. A total of 17 QTL were detected under two growing seasons, including 5 for hundred grain weight, 4 for hundred kernel weight, 5 for hundred grain shell weight and 3 for grain shell rate, explaining 3.76%～48.65% of the phenotypic variance. The QTL cluster qC1.2 contained each one stable major QTL for the four tested traits, which overlapped with the reported stable major QTL for shell type and hundred grain weight. These results provide a theoretical basis for fine mapping, cloning of genes and molecular improvement of grain shell rate-related traits in tartary buckwheat.