<p indent=0mm>Leaf is an important organ of rice, and it is the main place for photosynthesis. Leaf morphology related traits such as leaf length, leaf width and leaf area can directly affect leaf photosynthetic efficiency. The study of quantitative trait loci (QTL) sites for morphological characters of rice flag leaf and the improvement of morphological characters of rice flag leaf by means of genetic breeding can provide theoretical basis for the cultivation of ideal plant type rice. In this study, an indica rice variety HZ was used as the male parent, and a japonica rice variety Nekken2 was used as the female parent. After F1 generation was obtained by cross-breeding, 120 recombinant inbred lines (RIL populations) were obtained from successive generations of self-crossing, which were used as experimental materials in this study. Leaf length, leaf width, leaf area of rice at tillering stage and mature stage were studied and analyzed after incubation under the same and appropriate conditions. At the same time, the genetic map was constructed by using the RIL population to locate the QTLs for the traits of leaf length, leaf width and leaf area in rice at tillering stage and mature stage, 35 QTLs related to leaf morphology were detected. There were 6 QTLs related to blade length (5 at tillering stage, 1 at maturation stage), LOD value of one of them was as high as 6.92; 8 QTLs related to blade width (detected only at tillering stage), LOD value of one was as high as 4.51; 21 QTLs related to blade area (12 at tillering stage, 9 at mature stage), LOD values of two of them were as high as 6.37 and 4.06 respectively. Through quantitative analysis of the candidate genes related to leaf length, leaf width and leaf area in these QTL regions, it was found that<italic> LOC_Os02g52040</italic>, <italic>LOC_Os03g46610</italic>,<italic> LOC_Os04g52230</italic>,<italic> LOC_Os04g42230</italic>,<italic> LOC_Os04g44150</italic>,<italic> LOC_Os04g52479</italic>,<italic> LOC_Os09g37400 </italic>and <italic>LOC_Os12g42020</italic> were significantly different in expression levels between the parents. Combined with the data of leaf length, leaf width and leaf area of the parents, we speculated that The high expressions of<italic> LOC_Os04g52230</italic>, <italic>LOC_Os04g44150</italic>,<italic> LOC_Os09g37400 </italic>and <italic>LOC_Os12g42020</italic> may promote the growth of leaf width and leaf area, while the high expressions of <italic>LOC_Os02g52040</italic>, <italic>LOC_Os03g46610 </italic>and <italic>LOC_Os04g52479 </italic>may inhibit the growth of rice flag leaves. Through the analysis of QTL in this study, QTL regulating leaf length, leaf width and leaf area of rice flag leaf were excavated, which provided a reference for cultivating new rice varieties with excellent plant type.