There was also a huge increase in the number of cases, with 14,840 people diagnosed with Covid-19.
Hubei has started using a broader definition to diagnose people - which accounts for most of the rise in cases.
China sacked two top officials in Hubei province hours after the new figures were revealed.
Until Wednesday's increases, the number of people with the virus in Hubei, where the outbreak emerged, was stabilising.
But the new cases and deaths in the province have pushed the national death toll above 1,350 - with close to 60,000 infections in total.
The World Health Organization (WHO) says it is seeking "further clarity" from China about the changes to how cases of the virus are being confirmed.
China has been accused of suppressing the full extent of the outbreak in the past, says the BBC's Nick Beake in Hong Kong.
Professor David Heymann, Professor of Infectious Disease Epidemiology at the London School of Hygiene and Tropical Medicine, said that what has happened in China is that they have changed the definition of what the disease really is - now they are taking people who have lesser symptoms.
"The deaths are quite worrisome. There is an increased number of deaths reported, but if you look overall at the total number of deaths and the total number of cases, the fatality ratio is about the same as it has been - but it is still high, as high as the death rate in influenza."
Only Hubei province - which accounts for more than 80 per cent of overall Chinese infections - is using the new definition to diagnose new cases.
Over the past 24 hours, in Hubei alone, nearly 15,000 people were moved into the infected column. This would have sent shockwaves around the world, but actually, if you consider Wednesday's cases by the old definition, the rate could well mean another day of decline: a completely different picture.
The Communist Party secretary in Hubei, Jiang Chaoliang, has been replaced by the Shanghai party chief, Ying Yong, state media reported. The party chief of the capital city, Wuhan, has also been relieved of his duties.
It is the first major change of Hubei party officials since the outbreak began.
Earlier this week, a number of health officials were "removed" from their jobs.