Raw data of species list, life form, carbon isotope ratio (δ¹³C) and nitrogen isotope ratio (δ¹⁵N) for all observations examined across the arid zone of northwestern China. Multi-annual mean precipitation (MAP, mm), multi-annual mean temperature (MAT, ^oC), potential evapotranspiration (PET, mm), sediment total carbon (STC), sediment total nitrogen (STN), longitude (Long.), latitude (Lat.) and altitude (Alt.) across the arid zone of northwestern China were also provided.

We examined the spatial pattern of the leaf δ¹³C and δ¹⁵N of macrophytes collected across the arid zone of northwestern China and tried to illustrate its relationship with environmental factors.