The death toll from yesterday's earthquake stood at 398 with some people still missing.
Authorities sent 11,000 police and firefighters, over 7,000 soldiers and armed police as rescuers raced to save more people caught under the mountains of rubble.
Eight planes and several helicopters have also been rushed to the site to carry supplies and ferry the wounded to hospitals as troops poured into the remote areas badly hit by the shallow quake.
Li immediately went to Longtoushan Township, the site of the epicentre and where the casualties and building demolitions were highest.
"Saving lives is the top priority. Don't stop! Spare no effort!" he said.
It was the worst to jolt the region in 100 years, causing higher-than-expected losses, the state-run Xinhua news agency said.
About 1,801 were injured in quake and 2.30 lakh people were needed to emergency evacuation, the Yunnan Civil Affairs Department said.
Nearly 80,000 rooms of 25,500 households collapsed in the quake and 1.24 lakh rooms of 39,200 households were seriously damaged, the department said.
Three are missing in Qiaojia. Rescuers are racing against time to save lives, the report said.
Rescuers dug out with their hands a five-year-old boy buried in debris this morning in a village in Longtoushan Township, one of the worst-hit areas.
The child had injuries to his legs and received immediate medical treatment.
"We found and successfully rescued a woman and a man, both in their forties in Longtoushan," said Li Jin, a paramilitary officer.
Rescuers offered counselling and water to the seriously injured woman and man during the rescue process.
"The adverse weather and steep valleys are causing great difficulties in the rescue operation," said Zhang Yong, head of the Blue Sky Rescue Team, whose 45 members arrived at Longtoushan last night.