The population of G46B/A232 RILs and the high-density genetic linkage map created by resequencing the population were used to map QTLs for internode diameter of reciprocal second internode and reciprocal third internode with the R/qtl software package and CIM method.A total of 3 QTLs for the diameter of reciprocal second internode and 7 QTLs for the diameter of reciprocal third inter nodes were detected，which were distributed on chromosomes 2，3，4，7，and 11.On chromosome 2，qRSID2-1 and qRTID2-1 are relatively close.qRSID2-2/qRTID2-2 and qRTID2-3 repeatedly detected in multiple trials may be the same QTL，with phenotypic contribution rates of 7.89%-12.36% and the physical interval within 100 kb on chromosome 2.The genetic study of the internode diameter of reciprocal second internode and reciprocal third internode in rice will lay a foundation for fine mapping QTLs for the internode diameter，which is beneficial to the molecular breeding and germplasm innovation of rice varieties with lodging resistance and ideal plant type.