Abstract: Based on the Lei-Ting balance-equation approach we have theoretically studied electron transport characteristics of two-dimensional electron Gas （2DEG） in the modulation-doped AlGaN/GaN heterostructure,with an accurate treatment of the realistic scatterings by impurities, acoustic phonons, and polar-optic phonons.Ohmic mobility in the lattice-temperature range of 0-300 K and hot-electron transport property are calculated. It is shown that, for an optimized AlGaN/GaN heterostructure, its ohmic mobility can reach 4×10⁶ cm² /Vs. In addition, the dependence of the ohmic mobility on the remote doping concentration and the spacer width is also discussed.