The invention discloses a solar cell. The solar cell comprises a silicon-based solar cell substrate; a silicon oxide film layer which is located on the surface of the backlight side of the silicon-based solar cell substrate; an aluminum oxide film layer which is located on the surface of one side, back on to the silicon-based solar cell substrate, of the silicon oxide film layer; a silicon nitridefilm layer which is located on the surface of one side, back on to the silicon-based solar cell substrate, of the aluminum oxide film layer; the back electrode which is located on the backlight sidesurface of the silicon-based solar cell substrate, and a front electrode which is located on the light receiving side surface of the silicon-based solar cell substrate. The surface of the backlight side of the silicon-based solar cell substrate is provided with the silicon oxide-aluminum oxide-silicon nitride three-layer passivation structure, so the composite current density of the surface of theback surface of the silicon-based solar cell substrate can be further reduced; the conversion efficiency of the solar cell can be effectively improved by reducing the internal current consumption ofthe solar cell. The invention also provides a preparation method of the solar cell, and the prepared solar cell also has the above beneficial effects.