A doubled haploid (DH) population with 150 lines,derived from a cross between two Chinese common wheat varieties ‘Hanxuan 10’ and ‘Lumai 14’ was used as the plant material to mapping quantitative trait loci (QTL) for seedling heat tolerance.The seedling traits,including root dry weight,shoot dry weight,seedling biomass,chlorophyll content,chlorophyll fluorescence parameters and their heat tolerance index (HTI) were measured under heat stress and normal temperature condition,respectively.The QTLs and QTL×environment interactions for these traits were detected using mixedmodelbased composite interval mapping method.The results showed that the female parent ‘Hanxuan 10’ was more tolerant to heat than the male parent ‘Lumai 14’ at seedling stage,and the DHLs exhibited transgressive segregations.The most QTLs for seedling traits located on chromosomes 2D,6B,3A,4A,5A and 7A,and that for HTIs located on 6A,6B,3A,2D,5A and 7A.The distribution of QTLs for seedling traits and their HTIs on chromosomes exhibit a trend of regionalization.The average phenotypic variance explained by single additive QTL and single epistatic QTL were 2.48% and 2.65%,and that for HTIs were 8.84% and 1.98%,respectively.A total of 13 additive and 28 pairs of epistatic QTL related to seedling traits or their HTI were located on all chromosomes except 4D and 6D under two temperature conditions.The genetic effect of the QTLs for seedling traits mainly was epistatic effect and for HTIs mainly additive effect.