Real Madrid have confirmed that the star is set to sign a contract extension tying him to the European champions until 2021
Widespread Spanish media reports on Sunday said Ronaldo will follow Gareth Bale, Luka Modric and Toni Kroos in signing a deal tying him to the European champions until 2021, by which time he would be 36.
"What he has to do is finish his career here," said Zidane despite another off-colour display by Ronaldo in Sunday's 3-0 win over Leganes.
"Cristiano is unique for what he has done and what he is going."
Zidane retired in 2006 after five years with Madrid.
"It is his dream to end his career here. I am happy that he can renew (his contract) and finish with this white shirt like I did a long time ago."
Ronaldo is by a distance Real's top-scorer of all-time having smashed 371 goals in 360 games.
However, he has now gone five games without scoring at the Bernabeu -- his longest drought since joining Real from Manchester United seven years ago.
"There is nothing wrong, he is not worried," insisted Zidane.
"He looks good, he is motivated, he likes to scores goals and even more so in this stadium, but he is calm."