Ighalo, 28, took the Premier League by storm with 15 league goals in debut season with Watford and made a surprise £20m (R331m) switch to the burgeoning Chinese top-flight on transfer deadline day on 31 January 2017.
His first season with Chen Jingang's men brought a return of 15 goals in 27 appearances to help his side finish in seventh place but African star admits the level of football and coaching shocked him since his arrival.
"Before I went there, people were saying the level of the Chinese League is very low and you are going to score a lot of goals," he told BBC Football, while on international duty with the Super Eagles.
"When I got there I saw a different football game. There are a lot of foreign coaches and foreign players improving the league and the league is getting tougher and stronger.
"When I went there I was expecting a lower class of the league but when I arrived I saw how tough it is and said this is not what I had heard about," Ighalo added.
"This is not what people were talking about. It's tough and it's difficult to score goals."