Paulinho scored nine goals in 49 appearances after joining Barcelona from Guangzhou Evergrande last summer in a €40m (£35.3m) move.
The deal taking him back to Guangzhou contains an option for the Chinese Super League side to purchase the midfielder outright.
Paulinho rose to prominence in his homeland for Sao Paulo-based Corinthians before he moved to Tottenham in 2013.
But he only managed 31 Premier League starts during his time in north London before making a surprise move to Guangzhou in a deal worth in the region of £10m.
Paulinho made 63 appearances over two seasons in his first spell with Guangzhou Evergrande.