The deal for the Nigerian centre forward is reported to be in the region of £20 million, and he has joined a side that finished in 12th position in the 16-team Super League last season.
Ighalo becomes the latest big name player to move to China following the likes of Carlos Tevez and Oscar to the cash-rich Asian league.
Forward unable to get going this season
Ighalo was an absolute revelation for the Hornets last term scoring 13 goals in the first half at last season at Vicarage Road.
Unfortunately, he has only got two goals sine mirroring the poor form of the team towards the end of the season. He has been a shadow of himself under Italian head coach Walter Mazzarri making only a handful of appearances and scoring just a couple of times.
Mazzarri has added to his forward options to fill the void left by Ighalo with attacking options coming into the club.
Hornets have been busy in January
Former West Ham United forward Mauro Zarate has joined on a two-and-a-half-year contract from Fiorentina and M’baye Niang moved to Hertfordshire on a loan deal for the rest of the season from Serie A Giants AC Milan.
It has been an equally busy day for the Hornets with a few players departing the club. Full-back Juan Carlos Paredes has joined Greek champions Olympiacos on loan for the rest of the season.
Young striker Jerome Sinclair has made a similar move to championship side Birmingham City while Adlene Guedioura is reported to be having a medical at Premier League rivals Middlesbrough.
Things have also gone well on the pitch for Mazzarri’s men after they pulled off a shock 2-1 victory over Arsenal at the Emirates Stadium.