With a score of 199.4 points in 20 shots, the 25-year-old Zhang handily defeated Vitalina Batsarashkina from Russia, the silver medallist with a score of 197.1. Anna Korakaki from Greece won the bronze.
Zhang kept China in top standing in the event after countrywoman and London 2012 and Beijing 2008 gold medallist Guo Wenjun failed to qualify for the finals, finishing in 30th place.
Zhang established her lead midway through the event and pulled away with a 10.9 perfect shot in the final rounds. Her score is an Olympic record under the new finals format.
Ranked fifth in the world, Zhang said she struggled in qualification, where she came in seventh out of eight finalists.
"I was pretty calm for the final actually, because the qualification was a bit tough for me," Zhang said.
China has six medals so far in the Games, Zhang's gold, two silvers and three bronzes.
"I am still feeling the competition, I am still in that mood, and winning at the Olympic Games was my goal since I was young," Zhang said.
(Reporting by Mary Milliken; Editing by Clare Fallon and Alison Williams)
