The Catalan boss admitted his former side are “the best team” but will not change his football philosophy against the Blues’ star-studded Group C hosts.
Guardiola said: “I would like to defend well and attack well but to change the way you think, the way you believe in playing football, it’s impossible.
“The players aren’t going to believe me (if I do that). Of course you adjust many things because it’s a special team, how they play, build up, high pressing, they control all the departments and you have to adjust - and try to be ourselves as much as possible."
City are second placed in Group C on four points, two behind leaders Barca.
The home side have no injury worries ahead of the game after Lionel Messi’s successful return to the first team against Deportivo at the weekend, while City are without injured duo Bacary Sagna and Fabian Delph.
On the emotions of returning to his former club Guardiola added: “I came back with Bayern… it’s always special for me to sit here.
“I’ve spent time here, this stadium is part of my life, I grew up here. It’s always special when I see people who I like to see. When you travel around, you remember places for the people you met.
“It’s a good test for us to play against the best team.”
Guardiola was asked what has changed at City since the Blues' defeats against Barcelona under former manager Manuel Pellegrini, and he reflected: “I was here two/three years ago and it was with Manuel, he is the first coach who was able to reach semi-finals so a lot of credit to him to help who came next.
“City were not in Europe for a long time, so you’re important in Europe when you’re there a long time, and that is our next target in the next years, to be there competing.
“I know what they are going to do tomorrow, what we’re going to try and we’ll see if we are able to do it.”