Almost 200 fire fighters and 48 fire engines were deployed to tackle the blaze, which broke out in a lower level market stall on Wednesday evening, the state-run Xinhua news agency reported.
Fire fighters Zhu Xiaolei and Zhang Yu died while searching for people who could have been left stranded in the fire, Xinhua quoted local fire officials as saying.
The 12-storey Dehui International Plaza normally houses thousands of people in its shopping centre and the upper office floors.
The fire reportedly began shortly after 8pm local time, as the shopping area was preparing to close.
After battling the blaze for several hours, by Thursday morning firefighters had been forced to retreat from the main fire fearing the tower may collapse.
Instead they focused their efforts on putting out the fire in a neighbouring hotel where it had spread from the Dehui building.
Guests staying in the 20-storey hotel were all safely evacuated, officials said.