Lodging is an important influencing factor that seriously reduces the yield and quality of rapeseed and is undesirable in mechanized production. Cultivation of rapeseed varieties with strong lodging resistance is an important measure to achieve mechanized production and high yield performance， while the focus of improving lodging resistance is to improve stem strength. Therefore， a recombinant inbred lines （RILs） population containing 197 mustard rapeseed lines was used in this paper. Six characters including stem diameter， fresh-dry ratio， stem filling degree， stem density， stem bending resistance and stem bending strength were investigated under two environmental conditions in Guiyang and Guiding in 2023， respectively. All 6 personality traits showed significant variation， ranging from 14.29%-41.35%， and were in line with a normal distribution. Correlation analysis under two environmental conditions shows a highly significant positive correlation in stem plumpness if compared to stem density and bending strength. Further observation was conducted on the microstructure of the stems of three types of materials showing high， medium， and low bending resistance. Compared to low resistance materials， high resistance materials have thicker cortex， more vascular bundles， tighter arrangement of vascular bundle， and a larger proportion of vascular bundle area. In addition， 4 QTL for stem thickness， 2 QTL for stem fresh-dry ratio， 2 QTL for stem plumpness， and 2 QTL for stem density； 4 QTL for stem bending resistance explained the phenotypic variation of 4.1%-5.1%； 9 QTL for stem strength explained the phenotypic variation of 7.5%-11.0%. The results of this study provided basic data information for future cloning of lodging resistance related genes in mustard rapeseed， becoming valuable for lodging resistance breeding in rapeseed.