A double haploid population derived from anther culture of ZYQ8/JX17, a typical indica and japonica hybrid, was used in this study. The inhibited effect of water-soluble extract of 123 DH pure lines leaves on the lettuce roots growth was investigated, and the QTLs analysis of rice allelopathy was carried out. Totally, four QTLs related to rice allelopathy were detected, and they were on chromosomes 3, 9, 10 and 12, respectively. The LOD scores were 3.40, 2.68. 2.75 and 3.08, respectively. Among them, additive effects of the QTLs on chromosomes 3 and 10 were 1.65 and 1.43, on chromosomes 9 and 12 were ?1.44 and ?1.58, respectively. Allelopathy characteristics of another three common rice varieties were also studied.