The study of the large grain material plays an important role in mining genes of grain shape trait, and can provide high quality germplasm resources for rice breeding. In this study, The F2 segregation population, which was derived from a cross between large grain material lg1 and indica variety 9311, was used to identify QTL with the data of the grain shape traits in 2014, 2015 and the combined data of two years, respectively. The results showed that 22 QTLs were detected on chromosome No. 1, 2, 3, 4, 5, 8 and 11, including 5 QTLs for grain length, 9 QTLs for grain width, and 8 QTLs for grain thickness. There were 3 QTLs detected repeatedly in three situations, including grain length QTL qGL-2-1, grain width QTL qGW-5-1 and grain thickness QTL qGT-5-1, whose alleles were derived from parent lg1. In addition, 7 QTLs were identified in two situations, and 12 QTLs were identified only in one situation. The qGL-2-1, qGW-2-3 and qGT-2-3 were located in the same interval RM5812-RM13174, indicating that they could be influenced by one gene which might be a new grain shape gene. The major QTLs qGL-1-2 and qGW-11-1 could be new QTL loci of grain shape trait. Most of the rest QTLs are cloned gene and some mapped QTLs. These results have built a foundation for further fine mapping and cloning genes of lg1 grain shape traits.