The present disclosure belongs to the technical field of N-type double-sided solar cells. Disclosed is an N-type double-sided solar cell preparation method. The preparation method comprises: sequentially forming a front aluminum oxide passivation layer and a front silicon nitride anti-reflection layer on a front face of an N-type silicon wafer. The front aluminum oxide passivation layer is prepared by using a plasma-enhanced atomic layer deposition method, and the deposition conditions thereof involve: any frequency in the frequency range of 40 kHz to 400 kHz is selected to be a radio-frequency power supply frequency, a gaseous aluminum source is first introduced into a plasma apparatus in a vacuum state, such that a layer of aluminum source molecules is adsorbed on the surface of the silicon wafer, and a gaseous oxygen source is then introduced, such that the oxygen source is ionized into plasma and reacts with the aluminum source to obtain aluminum oxide. An oxygen source is ionized into plasma in a plasma apparatus, and the plasma has relatively high energy and activity, and can be quickly combined with aluminum source molecules which are adsorbed on an N-type silicon wafer, so as to generate an aluminum oxide film, such that the open-circuit voltage and the conversion efficiency of an N-type double-sided solar cell are improved.