Similar to other canned products, such as vegetables, canned soup lasts for up to 2 years if it is unopened. Often, canned products list a best-by date, which is not the same as an expiration date. Canned products like soup are still edible after the best-by date passes; however, there may be a noticeable loss of flavor.
The can should be in good condition. Before using any cans that are dented or show signs of rust, examine the soup closely and discard if it may have gone bad. Cans that are bloated should be discarded as the food has likely gone bad.