Observations show that there is a acceleration region on the high-latitude auroral field lines at the altitudes ranging from 2000 km-8000 km.It is pointed out in this paper that plasma sheet electrons are accelerated by the electrostatic waves turbulence and the large scale DCparallel electric field within-the acceleration region to form inverted-Vstructures.The equation of the electron energy spectrum is derived using the quasi-linear kinetic equation,and the solution of the energy spectrum is obtained.The main characters of the electron energy spectrum can be explained by this theory.