Ronaldo has been linked with a move away from Spain in recent months and PSG are considered one of the few clubs in world football that could realistically negotiate a transfer.
"Ronaldo is one of the best players in the world. He scores in almost every match. He can make a huge difference individually," Pastore told L'Equipe.
"If he would sign for Paris, it would be wonderful for the club and for the players already at the club. So if he could come, I would say yes."
PSG currently top Ligue 1 with 22 points.