The blasts took place at 9:30 am (local time) at the Fuwa Engineering Manufacturing Co Ltd at the Shunde District of industrial city Foshan, local official said.
17 people were killed in the blast while 33 others were injured, state-run Xinhua news agency reported.
The blast occurred when the factory was closed for cleaning. All the injured people were rushed to nearby hospitals.
The sound of the explosions were heard one km away.
Guangdong Province is one of China's largest manufacturing base.