Guo was aiming to set a new solo non-stop trans-Pacific world record from San Francisco to Shanghai
"Guo was last heard just after 15:00 Tuesday Beijing time (0700 GMT) when his trimaran sailed 900 nautical miles off the west of Hawaii," the official Xinhua news agency said, citing his team.
"All attempts to contact the sailor have failed," it said, adding that a search aircraft from Honolulu had found Guo's boat -- with the sail broken off -- but did not find the yachtsman on deck.
Guo, 51, was aiming to set a new solo non-stop trans-Pacific world record from San Francisco to Shanghai, setting sail on October 19.
In 2013 the former scientist became the first sailor from China to complete a non-stop solo circumnavigation of the globe.