The retailer said it was part of a £10m cost-cutting plan announced last month - when it issued a profits warning after a weak performance over the Christmas period.
It aims to redeploy staff affected by the cuts and the changes will not mean any store closures.
Debenhams said last year that ten stores were under review for closure if they became unprofitable.
Two stores - in Eltham and Farnborough - closed at the end of January under that review, affecting a total of 87 workers.
Announcing the latest cuts on Thursday, a spokesperson said the company had "undertaken a review of our store structure".
"The review has identified significant cost savings by reducing the complexity of management roles in stores as well as processes to optimise and standardise ways of working.
"The effect is that potentially 320 positions are at risk of redundancy - approximately 25% of store management roles."
"We are currently consulting with individuals affected and will seek redeployment opportunities where possible. We envisage our new structure being fully in place by the end of March."
The move follows a round of managerial roles going in the supermarket sector, with thousands of posts facing the axe at Tesco, Sainsbury's and Morrisons.