A fully sealed liquid crystal projection optical unit device with a high-efficiency heat dissipation function includes: a hermetically sealed housing having an accommodation space therein; a light source, a first heat pipe radiator module, a first heat dissipation fan and a second heat dissipation fan, which are disposed outside the hermetically sealed housing; a first optical module, a second optical module and a liquid crystal screen, which are installed in the hermetically sealed housing; and a second heat pipe radiator module and a driving fan, wherein the first heat dissipation fin is fixedly installed outside the hermetically sealed housing and located close to the second heat dissipation fan, the second heat dissipation fan is in communication with the first heat dissipation fin through an air duct, and the first heat dissipation fin is in communication with the second heat dissipation fin directly or through the heat pipe.