In this paper, we analyzed the contribution of pure DNA factors to heterosis using quantitative trait genes (QTG) in two randomly selected strains from a recombinant inbred line of Gossypium hirsutum. According to a set of QTL mapping results, combined with analysis of DNA recombinant fragment sources in the two strains and QTL association analysis with their field traits, we hypothesize a view of “dominance + overdominance + epistasis”. That is, additive and additive epistasis may be the genetic basis of heterosis, and dominance, overdominance and epistasis may be the modes of heterosis action. Based on the heterosis results of this study, we also suggest a molecular mechanism for heterosis, and explain, in detail, with two randomly selected strains as examples. The male and female parent-derived additive epistatic QTLs of upper half mean length in LG01 and LG03 produced a trait variance of 2.99-3.52 compared with the female parent-derived loci. The trait of bolls per plant was controlled by two pairs of additive epistatic QTLs in LG02 and LG07, which were derived from both female and male parents. The QTLs were reciprocally interacted and produced a trait variance of 0.86. An initial concept of “super-hybrid cotton” was raised according to the nature of additive effect, that is genetic stability. In this paper, we analyzed the contribution of pure DNA factors to heterosis using quantitative trait genes (QTG) in two randomly selected strains from a recombinant inbred line of Gossypium hirsutum. According to a set of QTL mapping results, combined with analysis of DNA recombinant fragment sources in the two strains and QTL association analysis with their field traits, we hypothesize a view of “dominance + overdominance + epistasis”. That is, additive and additive epistasis may the genetic basis of heterosis, and dominance, overdominance and Based on the heterosis results of this study, we also suggest a molecular mechanism for heterosis, and explain, in detail, with two randomly selected strains as examples. The male and female parent-derived additive epistatic QTLs of upper half mean length in LG01 and LG03 produced a trait variance of 2.99-3.52 compared with the female parent-derived loci. The trait of bolls per plant was cont was initially derived from both female and male parents. The QTLs were reciprocally interacted and produced a trait variance of 0.86. An initial concept of “super-hybrid cotton ” was raised by two pairs of additive epistatic QTLs in LG02 and LG07, which were derived from both female and male parents. according to the nature of additive effect, that is genetic success.