The Chinese Super League limits the number of foreign players each team can have and Jiangsu reached their quota by signing the Anderlecht striker, Xinhua news agency said.
Like Real Madrid's Bale, Santini is aged 30 and an attacker, although he enjoys nothing like the profile or reputation of the pacy Welshman.
With the Chinese transfer window closing on Wednesday, Jiangsu moved for Santini, saying: "He will greatly enrich the team's offensive tactics in the Chinese Super League."
It comes a day after Bale's move to China collapsed because of wrangling between Real and Jiangsu over the fee, a source told AFP.
Bale, who has been in the Spanish capital since 2013, had been expected to join the CSL outfit on a three-year deal worth over US$1 million a week.
Real boss Zinedine Zidane has made no secret of his wish to get rid of Bale and said he thought it would be "best for everyone" if his departure could be arranged quickly.
Bale's agent branded that "disrespectful" of a player who helped the side to a Spanish league title and four Champions Leagues since arriving from Tottenham six years ago.
However, injuries have limited Bale to fewer than 80 starts in La Liga in the last four seasons.
He has also been the subject of criticism in the Spanish media for his struggles with the language, and for the amount of time he spent on the golf course.