Liu Xinting was driving on his lunch break from work when an oncoming car swerved off the road and into a lake.
Mr Liu dived in to the lake as the car sank, rescuing all four people inside including a pregnant woman.
Hearing of the rescue, a local company offered the unusual fish head reward.
"There was no time for me to think or be scared, the fastest thing I could do was save lives," Mr Liu told the local Hangzhou Daily.
"It is hazardous to jump into the water without taking off your shoes and clothes," he said. "But the situation was too urgent."