Amir Ghafour scored a match-high 17 points for Iran from 16 attacks and one block, while Seyed Mohammad Mousavi contributed 12 points, 8 from attack hits.
Libin Liu led China with 17 points.
“The loss to Australia was a warning call that brought us back to the tournament. We played with more confidence. We stayed focused and enjoyed playing against China,” said Montenegrin head coach of Iran, Igor Kolakovic.
Iran will next take on India, while China goes up against Australia on Wednesday.
The Tehran championship also serves as the Tokyo 2020 Asian Olympic qualification tournament with the top-eight teams making it to the Olympic qualifiers.
The 2020 Men's Asian Olympic Qualification Tournament will be held in Jiangmen, China from January 7 to 12, 2020.