Preheat oven to 350 degrees F. Grease 13 x 9 inch baking pan.
Stir together the pumpkin, evaporated milk, eggs, sugar and pumpkin pie spice until smooth. Pour into prepared pan. Scatter dry cake mix over pumpkin mixture. Sprinkle with pecans. Pour melted butter evenly over top.
Bake 50 to 60 minutes or until it tests done. Cool completely and refrigerate.