The monster storm hit Wenling city early Saturday, packing winds of almost 190 kilometres per hour (120 miles per hour) and generating waves several metres high along the coast.
More than 2500 residents in areas prone to floods have been evacuated.
Around 3,200 flights have been cancelled due to the typhoon, state broadcaster CCTV has reported.
More than 1 million people were evacuated before the typhoon made landfall at about 1am local time (1pm Friday ET), with the government opening 122,000 disaster avoidance and resettlement sites, according to a report from Chinese state-run press agency Xinhua.
China was also hit by a magnitude six quake just a day ago, so experts are warning that this, alongside the typhoon, could cause more landslides due to the unstable ground.
On Sunday, footage from CCTV showed rescue workers on boats navigating through Linhai city, where streets were completely submerged in muddy water.
On Friday morning, China's National Meteorological Center issued a top-level red alert for Lekima with a maximum wind force reaching 209 km/h.
Power blackouts affected about 2.72 million households in Zhejiang as strong wind and rain downed electricity transmission lines, state media reported.
Coastal businesses in Zhejiang were shut and the Ministry of Emergency Management warned of potential risk of fire, explosions and toxic gas leaks at chemical parks and oil refineries. Hundreds of flights to and from Taiwan were cancelled, and some 16,000 people were slated to be evacuated in Shanghai, according to the Shanghai Daily.
As of Saturday morning, 253,000 people in Shanghai have been relocated, with part of the city's rail transit services including the maglev train temporarily suspended.