Negin Rasoulipour led the Iranians with 20 points, while Tsatsral Bayarmaa and Khulan Onolbaatar each scored 10 points for Mongolia.
Iran previously achieved an impressive 82-32 win against the Cook Islands and will face Thailand in its next Pool B match on Wednesday.
The tournament is currently taking place in Shenzhen, China.
Group A comprises Chinese Taipei, Kazakhstan, India, and Tahiti, while Group B includes Iran, Thailand, Mongolia, and the Cook Islands.
The team that finishes at the top of the tournament will earn promotion to Division A.