We report the THEMIS tail observation of electron injection with thin plasma boundary layers propagation earthwar.The electron injection displays little dispersion,both perpendicular and parallel accelerations have been observed,and is closely associated with Dipolarization Fronts (DFs) and Bsty Bulk Flows (BBF).The thickness of the thin plasma boundary layer is estimated to be comparable to the ion inertial length.Important physics and multiple scale coupling occurs at non-MHD scales (ion and electron scales) with non-adiabatic processes in the electron injection region and thin plasma boundary layer.Strong of spikes of large amplitude of electric fields with both parallel and perpendicular component to the ambient magnetic field are observed coincident with the electron injection and thin plasma boundary layer.Clear signature of non-gyrotropic energetic electron distributions was found in the electron injection region.Nonlinear electrostatic structures such as ElectroStatic Waves (ESWs) and Double Layers (DLs) are observed near thin plasma boundary layer.Ahead of the electron injection fronts enhancement of electromagnetic waves with the phase velocity comparable to Alfven speed were observed along with greatly enhanced electrostatic like waves with the phase velocities much larger than Alfven speed are observed just near the thin plasma boundary layer.It is suggested that in addition to the Betatron and Fermi acceleration processes,electric fields,electrostatic structures and waves may play important role in the acceleration and energization of electrons.