The weak localization and weak antilocalization effects in the coherent scattering of two dimensional electron gas(2DEG) have been observed in Al0.22Ga0.78N/GaN heterostructures by the magneto-transport measurement. The change of magnetoresistance from positive to negative under a perpendicular low magnetic field indicates that electron spin-orbit scattering caused by crystal field exists in Al0.22Ga0.78N/GaN heterojunction. The relation between the spin-orbit scattering time and the temperature is discussed for 2DEG, the inelastic scattering time measured by experiment shows a strong temperature dependence according to T-1 rule, which indicates that the electron-electron scattering with small energy transfer is the dominant inelastic process.