The meteorological department of Shanghai recorded an air temperature of 40.9 degrees Celsius (105.6 degrees Fahrenheit) at 2 p.m. Friday
It is the highest temperature record in the city in 145 years.
A red alert for extreme temperatures was issued by the Shanghai Central Meteorological Observatory on Friday.
The heatwave has been stifling Shanghai since the beginning of the month.
Friday marks the 11th consecutive day of summer heat with highs of 39 degrees Celsius.
The red alert was downgraded to an orange alert Friday afternoon, but many places in Shanghai are still coping with temperatures above 37 degrees.
Residents are hoping for a cooling wind or storm, but the weather bureau says that is unlikely to happen.
Four more sweltering days are forecast with highs of 40 degrees Celsius.
(With inputs from Xinhua)