Chang and Chen have been unbeatable in global diving events in recent years, winning gold at three straight world championships in 2022, 2023 and 2024.
They extended that run of dominance into the Olympic arena on Saturday, romping to victory with a total of 337.68 points.
That left them comfortably ahead of the American duo of Sarah Bacon and Kassidy Cook, who took silver with 314.64pts.
Britain's Yasmin Harper and Scarlett Mew Jensen won bronze with a final total of 302.28.
Chang and Chen's victory launched China's bid for a potential sweep of Olympic diving golds.
Chinese divers won seven out of eight gold medals in Tokyo three years ago.
The diving powerhouse has ruled the 3m springboard synchronised event since its introduction at the 2000 Sydney Olympics, winning gold on six out of seven occasions.
