Trimble replaces Timoci Nagusa on the right wing, Wallace comes in for Darren Cave in the centre and Ian Humphreys will start at out-half, with Niall O'Connor returning to the bench.
Phoenix Ulster Rugby Academy player Jamie Smith retains his place at full-back and is set to make his home debut in front of a capacity Ravenhill crowd.
Up front, Bryan Young makes way for Court at loosehead prop, with Nigel Brady and BJ Botha retained at hooker and tighthead prop respectively.
The second row is unchanged. The returning Ferris starts at blindside flanker, with Willie Faloon at openside and Chris Henry will once again captain the side from number 8.
Ulster coach Brian McLaughlin said: "We were very disappointed after last weekend in Dublin. I thought that we competed well but should have made a lot more of our scoring opportunities - we definitely deserved at least something from that game.
"It is Munster this Saturday, a home match at Ravenhill. We have to make sure we are up for the game, we have to compete and we have to make sure we beat them at Ravenhill.
"We have to go to town with them up front and we have to show that we are more than capable of dealing with them."
"At training this week we have worked hard in certain areas of the pitch, we've put down patterns of play we'll be using and it's just a matter of us holding onto the football and making the best use of it possible."
Looking forward to pulling on the white jersey again, Andrew Trimble said: "I think any opportunity to play against another province is always a great experience.
"Munster at Ravenhill, it is just brilliant, especially after the last couple of weeks away from home when we haven't got the results we were after.
"We have performed in little bits and pieces, but we haven't got the results we wanted so this is a great opportunity to put things right in front of our home crowd at Ravenhill."
ULSTER (v Munster): Jamie Smith; Andrew Trimble, Ian Whitten, Paddy Wallace, Simon Danielli; Ian Humphreys, Isaac Boss; Tom Court, Nigel Brady, BJ Botha, Ed O'Donoghue, Dan Tuohy, Stephen Ferris, Willie Faloon, Chris Henry (capt).
Replacements: Andy Kyriacou, Declan Fitzpatrick, Ryan Caldwell, Thomas Anderson, Cillian Willis, Niall O'Connor, Timoci Nagusa.