The invention discloses a high-strength heat-resistant corrosion-resistant polyurethane board which is prepared from diisocyanate, polycarbonate dibasic alcohol, dioctyl azelate, ethoxylated alkylphenol ammonium sulfate, toluene diisocyanate, heavy calcium carbonate, carbon black, nano attapulgite, nano silicon dioxide, bisphenol a diglycidyl ether, epoxy octyl stearate, a modified filler, methylsilicone oil, sulfur, a phenolic resin, a curing agent, melamine, hypophosphate, a flame-retardant synergistic agent, triallyl isocyanurate, dicumyl peroxide, 3,5-dimethylthiotoluylene diamine and a copper sheet. The invention also discloses a preparation method of the high-strength heat-resistant corrosion-resistant polyurethane board. The polyurethane board has the advantages of high strength, excellent heat resistance and excellent corrosion resistance.