St. Ajstrup Church's choir and nave are in the Romanesque style, built of granite ashlars on a bevelled base. The tower is built of granite ashlars and mediaeval large bricks; it is not as old as the choir and nave. The choir and the nave are separated by a rebuilt choir bow.
The altarpiece makes a portal over Thorvaldsen’s Krist in plaster cast. The nave is a roman four-leaf clover form and stands on a newer foot. In the choir, you will find a tombstone over Mathias Mørch and Karen Glerup.