It was the third gold medal in as many events for the Chinese, who are trying to repeat their performance from the most recent world championships when they won all eight titles. They won seven out of eight at the 2008 Beijing Olympics.
Chen captured this event four years ago with another partner and she also won the individual platform competition in Beijing.
The Chinese duo actually was in third place after the first of five dives in the final. Chen and Wang then did a back dive on their second effort of the finals and took the lead for good with scores of 9.5 across the board.
They had only one score of less than 9.5 the rest of the way.
China's final total was 368.40 while silver-medal winners Alejandro Orozco Loza and Paola Espinosa Sanchez of Mexico finished at 343.32.
The bronze medal went to Canadians Roseline Filion and Meaghan Benefeito, who scored 337.62.
China has won 16 of the last 19 diving competitions at the Olympics.