When electrons are accelerated by the ponderomotive force of an intense short-pulse laser, the electrons are accelerated at the head of the laser and they lose their energy gained at the tail of the laser. Therefore the electrons cannot finally obtain the laser energy. In this research, an overdense slab plasma separator is introduced in order to separate the accelerated electrons from the laser, just before they enter the deceleration phase. The laser is reflected by the plasma separator, so the electrons pass through the thin plasma separator without a significant influence and are successfully accelerated.