Thousands of people have been evacuated and tens of thousands of troops are on standby ahead of Typhoon Dujuan's arrival in Taiwan.
Taiwan's Central Weather Bureau upgraded Dujuan to a "strong typhoon" on Sunday - also known as "super typhoon" by some weather agencies.
Landfall in Taiwan is expected at 11:00 pm local time (1500 GMT), bringing heavy rain and high winds.
The storm is expected to weaken before reaching mainland China on Tuesday.
Before hitting Taiwan, Dujuan will pass close to Japan's Ishigaki island, where the Japan Meteorological Agency has warned it could cause 13 metre-high waves
Around 3,000 people, mostly tourists, were evacuated from Taiwan's Green Island and Orchid Island on Sunday, with around 4,000 more moved from vulnerable areas on Monday.
Some of those were transported from the hot spring town of Wulai, near Taipei. Wulai was badly hit by Typhoon Soudelor in August and the Weather Bureau warned that rubble left over from that could cause more damage this time.
Soudelor, the most powerful storm of the season so far, killed at least eight people in Taiwan and a further 21 in China.
The storm has already disrupted many people's plans for the mid-autumn festival long weekend. Hundreds of flights and many ferry services have been suspended.
US rock band Bon Jovi also cancelled a concert planned for Monday night - their first gig in Taiwan in decades - though they are currently still planning to perform on Tuesday.
Source : bbc