Team Melli defeated host China in straight sets (25-22, 25-20, 25-21) at Jiangmen Hall.
Iran, as Pool A winner, will face South Korea on sturdy and China play Qatar.
The two winners in the semi-finals set up a final showdown, where only the eventual winner will secure its berth to the Tokyo 2020. The two losing sides will fight it out in the third-place playoff encounter.