Couch and Barrow, who claimed third overall in last year’s six-leg series, scored 289.62 points at the famous Water Cube venue, which hosted the 2008 Olympic Games.
Home favourites Ruolin Chen and Huixia Liu eased to victory with a score of 345.36.
Second were Malaysia’s Mun Yee Leong and Jun Hoong Cheong with 320.28 points and third place went to Canada’s Commonwealth Games champions Meaghan Benfeito and Roseline Filion on 310.86.
Couch and Barrow will dive again on Sunday in the individual event. They are both drawn in the same semi-final for that competition.
Tom Daley will also dive on Sunday in the men’s individual platform.