In this dataset, the basic environmental parameters, branched glycerol dialkyl glycerol tetraethers (brGDGTs) and soil bacterial community composition along an aridity soil transect in Inner Mongolia are included. In total, 32 surface soil samples (0-10 cm) were investigated, and the vegetation is characteried as desert steppe, typical steppe, and meadow steppe, repectively. The brGDGTs were extracted uisng a modified Bligh-Dyer method at the Institute of Botany, Chinese Academy of Sciences, and were subquently analyzed on a ultra high performance liquid chromatography mass spectrometer (UHPLC-MS) at Utrecht University. The bacterial DNA was analyzed using the MoBio PowerSoil DNA isolation Kit, and were further processed at the Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences.