Insulating structure for solidifying castings

The invention provides an insulating structure for solidifying castings. The insulating structure comprises a riser bush, two first insulating layers and two second insulating layers, wherein the riser bush is cylindrical and is arranged in a riser bush accommodation part of a die cavity of a sand mold; the first insulating layers are arranged in corresponding first insulating layer accommodation parts of the die cavity of the sand mold; the second insulating layers are arranged in corresponding second insulating layer accommodation parts of the die cavity of the sand mold; the die cavity of the sand mold is provided with a platy casting forming cavity; the platy casting forming cavity is communicated to the riser bush accommodation part and the two second insulating layer accommodation parts, are protruded out of the riser bush accommodation part and the two second insulating layer accommodation parts along two opposite sides of the Y direction in a rectangular form, and is downwards protruded along the Z direction; molten casting materials are poured into the platy casting forming cavity and are solidified to form a platy casting; the riser bush, the first insulating layers and the second insulating layers are made of the same insulating materials, and have good insulating performance and high-temperature thermal stability; in the casting process, sequential solidification between the castings and a riser is guaranteed, so that the technological yield of the castings is improved.