Abstract: The present invention relates to a ceramic composition and a porous ceramic insulating material comprising the same, which is widely used as a core material in sandwich panels or fire doors. The ceramic composition comprises 44-60 wt % of glass powder, 8-15 wt % of fly ash, 4-8 wt % of surface treatment agent, and 23-29 wt % of water glass. The porous ceramic insulating material manufactured from the composition is lightweight and is an environmentally friendly material which generates no toxic gas when it catches fire. The ceramic insulating material can be produced at a low temperature of 800˜900° C., and thus has low production cost. In addition, it can be continuously manufactured in a sheet form.