The Paraguay international has signed a four-year contract with the Super League club and will move for a fee of £9.7 million.
It has been reported in Germany that the 27-year-old will earn around £5.5m a year for the duration of his contract.
"Lucas Barrios won two Bundesliga titles with us and in 82 league games scored 39 goals... so that is why we met his wish to change clubs and play first team football," Dortmund said in a statement.
Barrios added: "I want to thank the many fans of Borussia Dortmund for their great support over the past three years. I will never forget my time here."
Barrios scored 16 goals in the league last season as Dortmund claimed their first title in nine years.
However, after picking an injury during last summer's Copa America, he has struggled for fitness and form and saw his place in the team taken by Poland striker Robert Lewandowski as Dortmund retained their title this term.
Barrios will link up with several other South American players at Guangzhao, including Argentine midfielder Dario Conca, who is reported to be on a contract worth around £6.5m a year.