Hangzhou, who finished 11th in the CSL last year and are led by former South Korea defender and coach Hong Myung-bo, said the 36-year-old had joined the club on a six-month deal.
"As the club's main foreign import, looking forward to seeing a good performance from Cahill in the Chinese Super League," the club said on its website.
"Tim Cahill good luck!"
Cahill, who spent eight seasons at Everton and had three years at New York Red Bulls, is Australia's most prolific scorer and had 11 goals in 28 appearances for Shenhua.
However, just months after signing on at Shenhua for another year he was told he was no longer part of Spanish coach Gregorio Manzano's plans for the 2016 campaign.
The CSL's 2016 season kicks off on March 4.
(Reporting by Ian Ransom; Editing by Peter Rutherford)
