You can compare a changeset item revision with:
Another revision of the same item.
A work file on disk.
(Windows Explorer and desktop client) Another item revision in the repository.
Open the Changeset dialog box.
Expand a changeset.
Do one of the following:
Windows Explorer and desktop client: right-click a new or modified item revision and select Compare with. The Compare Items dialog box appears.
Web client: select a new or modified item revision and on the toolbar click Compare. The Show Differences dialog box appears.
For more information see Comparing Item Revisions and Files.
Click OK.