NOVELTY - A solar polyurethane insulating material contains component A composed of isocyanate (NCO) from methylene diphenyl diisocyanate (MDI) and component B composed of bio-based polyether polyol, deionized water, sorbitol polyether, cane sugar polyether, leveling agent, and 2-3 pts. wt. catalyst in which weight ratio component A:component B is 1.36:1, bio-based polyether polyol has 1000-12000 molecular weight distribution, 490 mg KOH/g hydroxyl value, and 3600 mPa.s viscosity at 25 degrees C, leveling agent is polyether-modified organic polysiloxane, and catalyst is N,N-dimethylcyclohexylamine.    USE - Solar polyurethane insulating material (claimed).    ADVANTAGE - The material has low device, high stability and heat coefficient, unique property, small viscosity, and good fluidity and foam stability, and does not shrink, deform, and expand, and preparation is simple and environment-friendly and has convenient operation and no ozone damage effect, poison, and side effect.    DETAILED DESCRIPTION - A solar polyurethane insulating material contains component A composed of 30-32 wt.% isocyanate (NCO) from methylene diphenyl diisocyanate (MDI) and component B composed of 35-40 pts. wt. bio-based polyether polyol, 6-8 pts. wt. deionized water, 25-29 pts. wt. sorbitol polyether, 31-35 pts. wt. cane sugar polyether, 2.2-2.8 pts. wt. leveling agent, and 2-3 pts. wt. catalyst in which weight ratio component A:component B is 1.36:1, bio-based polyether polyol has 1000-12000 molecular weight distribution, 490 mg KOH/g hydroxyl value, and 3600 mPa.s viscosity at 25 degrees C, leveling agent is polyether-modified organic polysiloxane, and catalyst is N,N-dimethylcyclohexylamine. An INDEPENDENT CLAIM is included for preparation of solar polyurethane insulating material which involves pumping component B raw materials in small container to obtain component B, adding component A, mixing, controlling temperature at 28-30 degrees C, mixing component A and component B at high-speed in high-pressure gun collision, pouring in solar water tank cavity, performing foaming process, and high-temperature curing in which component A filling pressure is 130-140 bar and component B filling pressure is 6 bar.