Chromosome segment identification of rice chromosome segment substitution line Z745 was conducted, and QTL mapping of panicle traits of secondary F2 population which was constructed by crossing with Nipponbare as the background parent and Z745 as the donor parent was studied,so as to find new QTL for panicle traits.The results showed that Z745 contained 17 substitution fragments,which were distributed on chromosomes 1,3—8,10 and 12.The replacement length was 26.1 Mb,and the average replacement length was 1.54 Mb.The panicle length,primary branch number,secondary branch number and grain number per panicle of Z745 were all significantly higher than those of Nipponbare.Twenty one QTLs of panicle traits were identified,which were distributed on nine substitutional segments,located on chromosomes 1,3—5,7—8,10 and 12.Among them,4 QTLs for panicle length were on chromosomes 1,4 and 7;4 QTLs for primary branch number were on chromosomes 1,5,7 and 8;6 QTLs for secondary branch number were on chromosomes 1,7,10 and 12;7 QTLs for grain number per panicle were on chromosomes1,3,7,8 and 10 respectively.The panicle length QTLs(qPL7-1,qPL7-2),secondary branch number QTL(qNSB7-1)and grain number per panicle QTL(qSPP1-1) located in this study had been reported,while the remaining ear trait QTLs had not been reported yet.