Companies and residents of the island of Luzon, which is home to millions of people, were opening windows and tying roofs that could be cut by strong winds.
"The rains will be strong and the winds are no joke … We may have a storm surge that could reach four floors," Michael Conag, a spokesman for local civil defense authorities, told AFP.
"This could destroy houses, especially improvised houses, which are the most common in coastal areas."
Authorities said some 10 million people in the Philippines are on the path of the storm, not including millions more on the densely populated coast of China.
Farmers in the region, who produce a significant portion of the Philippines' corn and rice, rushed to bring crops that could be destroyed by the floods.
Thousands began evacuating in the coastal areas of the northern tip of the main Philippine island of Luzon, where the storm is expected to make landfall early Saturday.
"We're really scared, they say (the typhoon) is so strong," said Delaila Pasion, who had fled her home. "We were too scared to stay."
"During the previous monsoon rains, half of our house was destroyed, so I wanted to take my grandchildren to a safe place," he told reporters.