The invention relates to the chemical technical field and discloses a high-temperature, high-
humidity and high-salt mist-resistant
polyurethane coating and a preparation method thereof, so as to solve the technical problem that in the prior art, the steel structure is relatively poor in
preservative effect. The
polyurethane coating is prepared from 1 part by weight of a main
coating and 0.08-0.15 part by weight of a curing agent; the main coating is prepared from the following components in parts by weight: 0.25-0.35 part of
fluorine-modified
acrylic resin, 0.25-0.35 part of hydroxy
acrylic resin, 0.001-0.002 part of a
polyurethane curing accelerator, 0.01-0.02 part of nanosilicon dioxide, 0.01-0.02 part of a hindered amine stabilizer, 0.002-0.008 part of a modified
polysilane defoaming agent, 0.2-0.3 part of
titanium dioxide, 0.15-0.20 part of talcum
powder and 0.05-0.10 part of dimethylbenzene; the curing agent is prepared from the following components in parts by weight: 0.3-0.4 part of
isophorone diisocyanate, 0.4-0.5 part of
hexamethylene diisocyanate, 0.05-0.15 part of
isobutyl acetate and 0.05-0.15 part of methoxy
propyl acetate. Furthermore, the
preservative effect of the steel structure is improved.