The invention discloses a method for producing a cell-derived combined inactivated vaccine against chicken Newcastle disease and avian influenza and a product. The method comprises the following steps: respectively inoculating chicken Newcastle disease strains and avian influenza strains with EB66 passage cells, harvesting and storing viruses when EID50 titers of the viruses are maximum; inactivating chicken Newcastle disease viruses and avian influenza viruses respectively; completely mixing the inactivated chicken Newcastle disease viruses and avian influenza viruses in Tween-80 to obtain avirus mixture; and adding a sterilized oil phase adjuvant into the virus mixture, and mixing and emulsifying to prepare the combined inactivated vaccine. In the preparation method provided by the invention, EB66 passage cell lines of duck embryonic stem cells are adopted to culture the chicken Newcastle disease viruses and the avian influenza viruses respectively; and then, the prepared combined inactivated vaccine has advantages of stable production process, small inter-batch difference, controllable quality, significantly improved yield and quality and the like.