Zou, whose bronze in Athens was China's first Olympic boxing medal, won gold at the Beijing Games and beat Thailand's Kaeo Pongprayoon in London last year to become the first light-flyweight to win three Olympic medals.
A popular figure in his country, the 31-year-old beat Mexican Eleazar Valenzuela with all three judges giving him a 40-36 victory amid huge cheers from his home fans at the Venetian Macau resort hotel.
Zou, also a three-time amateur world champion, has signed a professional contract with Bob Arum's Top Rank promotion, which also has eight-division world champion Manny Pacquiao and WBO welterweight title holder Timothy Bradley in its ranks.
Officials in Macau, the world's largest gambling destination, are aiming to transform the casino-dominated enclave into an international leisure and tourism destination.
The southern Chinese hub, where gambling revenues reached $38 billion in 2012 - six times that of Las Vegas - is heavily reliant on the casino industry.
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