Megaripple stripes (MRS) are enigmatic aeolian bedform patterns which are composed of crosswind alternating, wind-parallel megaripple corridors (MRCs) and smaller bedform corridors (SBCs). Compared to SBCs, MRCs have taller bedforms, longer wavelengths, and coarser surface sediments. However, their morphology, grain size, and internal structure are poorly understood. Numerous MRS have been identified in the central-southern edge of the Qaidam Basin. Unmanned Aerial Vehicle (UAV) images and 3D cloud point data were used to explore the morphological properties of MRS, and sediment samples were collected for grain size analysis. The sedimentary characteristics were analyzed through sections of MRC, transition zone between MRC and SBC, and SBC. The results show that the downwind and crosswind wavelengths of MRCs, along with the downwind wavelength of SBCs, decrease in the downwind direction. Conversely, the crosswind wavelength of SBCs displays an increasing trend. The crestline of MRS becomes progressively curved along the downwind direction. The average wavelength of MRCs is 8.51 m, with a height of 0.46 m. The average wavelength and height of SBCs are 1.69 m and 0.07 m, respectively. SBCs are smaller and more densely distributed than MRCs. Most values of the Ripple Index (RI) of MRS clustered between 11 and 60. MRCs exhibit a relatively symmetrical cross-sectional profile, while SBCs exhibit comparatively poor symmetry. MRCs are mainly composed of gravel and very fine sand, with accounting for 63.67 % of content in total. In SBCs, the prevalent grain sizes are very coarse sand and fine sand, accounting for 48.42 % of content in total. MRS display poor sorting, presenting a predominantly positive skewness and wide to very wide peaks. The thickness and inclination of laminae in middle layer 1 gradually decrease from MRCs to SBCs. The sedimentary structure of MRS provides insights into the grain migration in downwind and crosswind directions during their formation.