The invention discloses a multifunctional isolation-level protective cap and a sealing method, and especially relates to a safety helmet capable of preventing infectious diseases, poison, dust,
haze and the like. The helmet comprises a safety helmet body, a neck sealing cover, an exhaust port, an exhaust filtering cover, a perspective area, an air inlet, an air inlet fan, an air
inlet flow expanding cavity, an air inlet filtering cover, a battery box, a safety helmet lining, an air inlet filtering cover support and an exhaust filtering cover support. The multifunctional isolation-level protective cap has the following advantages that: the whole head is completely sealed in the protective cap without wearing a
mask, so that the goggles are completely protected, and the forced
filtration airinlet fan is installed, so that air in the helmet flows, sufficient
fresh air is provided all the time, the problems of difficulty in
breathing and stuffiness are thoroughly solved, and the
head injury caused by collision and
foreign matter smashing can be borne or reduced.