The invention discloses an N-type PERT double-sided battery structure suitable for being thinned and preparation method thereof. The structure comprises a silicon substrate. On the front face of the silicon substrate, an n+ lightly doped layer and a local n++heavily doped region are formed. On the n+ lightly doped layer, a passivation antireflection layer is formed through a technology step. A cathode is guided out from the n++heavily doped region. On the back face of the silicon substrate, a p+ doped layer is formed and a second passivation antireflection layer is formed through a technology step. An anode is guided out from the p+ doped layer. When the n+ doped layer is transferred to the front face of a battery, the light blocking size by metal grating wires can be reduced and the contact and composition of electrodes are reduced; in addition, the formed n++ local heavily doped region increases the open circuit voltage and the short circuit current of the battery substantially, and at the same time, enables the square resistance of the n+ doped layer to be raised to a higher level. This is favorable to increase the surface passivation effect. As both the first passivation antireflection layer and the second passivation antireflection layer are prepared through one technology step, the technology manufacturing procedures are optimized greatly, therefore, increasing the production efficiency and reducing the manufacturing cost.