Early maturity is one of the target traits in upland cotton（Gossypium hirsutum L.）breeding，and identification of QTL related to early-maturity is of practical value. In our study，we crossed early-maturity 019 line（EM019）with a late-maturing cultivar Lumianyan 37（LMY37），followed by continuous self-pollination and construction of a recombinant inbred line（RIL）population composed of 312 lines. The RIL population was planted in Linqing（2019，2020 and 2021）and Xinjiang（2019）. We used composite interval mapping （CIM）method to detect quantitative trait locus（QTLs）underlying the flowering time（FT），percentage of open bolls（POB），boll weight（BW）and lint percentage（LP）. A total of twenty-one early-maturity QTL had been identified，and seven QTL were detected with the additive effect ranging from 0.3 to 1.01，explaining 2.56%~17.71% of the phenotypic variation. Eight QTL associating with POB were identified with the additive effect of 5.81~-2.39，explaining 4.66%~20.44% of the phenotypic variation. These QTL were mainly distributed on Chromosomes A05，D03 andD08. A QTL cluster was found on Chromosome D08，in which 124 candidate genes were annotated based on the transcriptome data of LMY37 and EM019 at different true leaf stages under long and short day treatments. Three strong related genes namely GH_D08G0636，GH_D08G0684 and GH_ D08G0948，have been identified. Altogether，these QTL identified from this study provided insight for future deciphering the molecular mechanisms of early-maturity related traits in cotton.