Abstract: Stem of plants can be used as animal grazing, wind erosion control, reduce water flow, increase evaporation and transpiration. In NW of Iran (East Azerbaijan province), rangelands was utilized with animal grazing and changed to agricultural land use; this vegetation is unsuitable vegetation coverage. Researchers studied Carthamus oxyacantha to determine its stem biomass characteristics. Data were collected with accidental sampling method (1x1 m) in this aria. In total of 4 plots were collected and 20 samples were studied in this research. Minimum, maximum and mean stem biomasses of this plant were 6.5, 20.3 and 10 g, respectively.