Insulation box for oil well

The utility model relates to a heat insulation box of an oil well for the heat insulation of oil in oil fields and water wells in the winter, which is characterized in that the heat insulation box is in a square box body structure; the box body is composed of a heat insulation layer (5) of hard polyurethane, a reinforcement framework (4), and a protective layer (6) of glass fibre reinforced plastics, wherein, an opening hole holding a pipe connecting wire (2) and an observation window (3) are arranged on the box body. The utility model can ensure the oil and the water wells to produce without heat at negative 35 DEG C, and has the characteristics of good heat insulation performance, convenient assembly and disassembly, and safety.