Preheat oven to 350 degrees. Spray a 9x13 baking dish with nonstick cooking spray.
Pour peach pie fillings into bottom of baking dish and evenly spread out.
In a medium bowl place dry cake mix and 7-up, stir to combine.
Pour batter over peach pie filling.
Place baking dish in oven and bake for 45 minutes to 1 hour. Check for doneness by inserting a toothpick into cake. It should pull out clean or have a few crumbs on it.