In the men's up to 80kg competition, Rostami triumphed with a lift of 236kg.
China's Gu Xiaofei was the silver medalist with 227kg, edging Egypt's Mohamed Elelfat into runner-up spot by a margin of 2kg.
Earlier on the day, Rostami’s countryman Nader Moradi won a silver medal in the men’s up to 72kg.
The 2019 World Para Powerlifting Championship is being held with the participation of more than 450 athletes from 79 countries and will end on July 20.