The invention relates to the technical field of electronic cigarettes, and in particular, relates to a porous ceramic for an electronic cigarette, an atomizing core containing the porous ceramic and apreparation method of the atomizing core. The porous ceramic for the electronic cigarette is composed of the following components in percentage by mass: 35 to 60 percent of ceramic powder, 5 to 40 percent of a pore forming agent, 5 to 30 percent of a sintering aid and 15 to 35 percent of a glue, wherein the glue is composed of the following components in percentage by mass: 20 to 40 percent of PE, 20 to 40 percent of PP, 1 to 10 percent of PE wax, 15 to 40 percent of paraffin and 1 to 10 percent of stearic acid or oleic acid. Through the mode, the porous ceramic with a uniform structure and adjustable pore diameter and porosity is prepared by adopting an injection molding process, so that the requirements of users on different pore diameters and different porosities of the porous ceramiccan be met; through the specific feeding sequence and an internal mixer, the materials are mixed more uniformly, the forming size is stable and is close to the net size, secondary machining is not needed, forming is easy and automatic, the production efficiency is high, and the production cost is low.