A tunnel oxide layer, an N-type bifacial crystalline silicon solar cell and a method for manufacturing the same are provided, which are relate to the field of crystalline silicon solar cells. The method for manufacturing the tunnel oxide layer includes forming excess -OH on a back side of a silicon wafer, and depositing the tunnel oxide layer on the back side of the silicon wafer by a Plasma Enhanced Atomic Layer Deposition method. The method for manufacturing the N-type bifacial crystalline silicon solar cell can include following steps: performing cleaning, texturing, boron diffusing, and alkaline polishing on an N-type silicon wafer, sequentially forming a P-type doped layer, a passivation layer, and an anti-reflection layer on a front side of the alkaline-polished N-type silicon wafer, and forming a tunnel oxide layer on a back side of the alkaline-polished N-type silicon wafer, followed by forming an N-type doped polysilicon layer, and after annealing, forming an anti-reflection layer. A SiO x layer obtained by the above method can be continuous and dense, and have a fast growth rate, an excellent impurity absorption effect and an excellent blocking effect. Moreover, a thickness of the SiO x layer can be accurate and controllable, and the SiO x layer has pinholes with a high density and a large size after high temperature annealing.