The federation said American legend Mayweather had pledged to "go all-out to use his influence and resources to support the Chinese boxing project in achieving excellent results at the Tokyo Olympics."
It made the announcement in a post dated Sunday on its official account on Chinese social media platform WeChat.
Mayweather made no mention of the appointment on his social media accounts, and the Chinese announcement gave no further details of his role.
Boxing legend Mayweather had a perfect 50-0 record in the ring with 27 knockouts. He won world titles in five different weight divisions and was considered the best pound-for-pound boxer in the sport.
The sport was once banned in China and it took until Athens 2004 for Zou Shiming to win the country's first Olympic medal, a light flyweight bronze.
Zou went on to claim gold at the next two games and there have been further successes since, especially after the introduction of women's boxing at London 2012.