Based on the gradient data in the near surface layer,  which were observed over the middle-Gansu semi-arid region of Loess Plateau from October 2003 to July 2005,  the bulk transfer coefficients for momentum and heat are estimated using the aerodynamic method. The resultsshow that bulk transfer coefficients for momentum and heat appear obviously daily variations,  and the maximum values are 5.6×10-3 and 6.7×10-3 , respectivelyaround noon in summer. The largest mean values of bulk transfer coefficients occurin milky\|ripening period of spring wheat,  and the second largest values occurin the early October due to the effect of plants. Mean values of bulk transfer coefficients for momentum and heat are 2.9×10-3and 3.1×10-3 , respectively during measurements period. Bulk transfer coefficients decrease with increasing wind speeds under unstable atmospheric condition,  and increase with decreasing wind speeds under stable atmospheric condition. Moreover,  bulk transfer coefficients over land surface of Loess Plateauare larger than those over land surface of Gobi,  grassland in plain,  ocean,  and smaller than those over land surface of urban and grassland in Tibetan Plateau.