Deco told Portuguese broadcasters SIC: "He (Mourinho) would come here and would impose his work style. What people [Barcelona fans] want is to win trophies."
Deco was part of Porto's 2004 Champions League-winning team under Mourinho, who is not universally popular at the Nou Camp after remarks he made while Chelsea coach.
However, Deco is confident the fans would welcome back the man who was part of the Barca set-up under Sir Bobby Robson and Louis van Gaal.
"Some polls here (Barcelona) show that people would be glad to have him (Mourinho)," said the Brazil-born Deco, who is expected to start on the bench against Real Madrid and made no secret of his desire for Mourinho to take over from Frank Rijkaard.
Deco said: "I would be happy because he is a great coach, a good friend with whom I had happy moments. If it happens I would be very happy."