Abstract: A linkage map consisting of 97 SSR markers was constructed using 123 F12 lines (recombinant inbred lines, RILs) derived from crossing between “Lemont” and “Dular” rice cultivars. QTL analysis was conducted for flag leaf photooxidation tolerance, including tolerance index (T) and sensitivity index (S). Using WinQTLcart 2.5 software, a total of eleven QTLs are detected with percentage variance explanation (PVE) of 6%~23%, and LOD of QTLs of 2.02~5.07. Of the QTLs, seven tolerance indices are detected on chromosomes 1, 2, 3, 6 and 8, with PVE of 6%~19%; four controlling sensitivity indices are detected on chromosomes 1, 3, 5 and 8, respectively explaining 19%, 23%, 6% and 7% of total phenotypic variation. On the basis of both traits, two QTLs for tolerance index and sensitivity index are co-localized around RM85~RM468 and RM408~RM250 respectively, which could explain negative significant correlation between tolerance index and sensitivity index, i.e . the pleiotrophic effect.