The invention provides a high-quantum efficiency microchannel plate photomultiplier, a bialkali photocathode and fabrication methods thereof. By the fabrication method, the photomultiplier has relatively high quantum efficiency. The photomultiplier comprises the bialkali photocathode, a reflection film, a focusing electrode, an electron dynode and a power supply pole, the bialkali photocathode, the electron multiplication pole and the focusing electrode are all arranged in a glass vacuum container, and the power supply pole penetrates through the glass vacuum container to be connected with an external circuit. The fabrication method comprises the steps of element potassium evaporation, element potassium and antimony ball evaporation and element caesium and antimony ball evaporation. The practical application shows that the fabrication method can be used for substantially improving the quantum efficiency of a large-size photomultiplier.