According to multiple reports in Portugal, Porto have sold the Brazilian for around €10m.
Soares, 29, has agreed a three-year deal with Tianjin worth €2m-per-season.
Porto finalised the sale of Soares over the weekend and he was excluded from first-team training on Sunday.
In his four seasons with Porto, Soares has scored 65 goals in 140 appearances.
However, Soares is happy to join Tianjin because of the salary which will earn him €6m over the duration of his contract.