178 recombinant inbred lines (F12) of crossing rice varieties Gang 46B with A232 were used to investigate the length,width and aspect ratio of flag leaves in Lingshui,Hainan province and Wuhan,Hubei Province. 14 QTLs in total including 5 flag leaf width QTLs,6 flag leaf length QTLs,and 3 flag leaf lengthto width ratio QTLs were detected,which were distributed on rice chromosomes 1,2,4,6,7,10 and 12. LOD values were ranged from 2.52 to 5.62. The contribution rate of a single QTL to phenotypic variation varied from 5.56% to 21.27%.