Provided is an inner lining for backpacks or handbags. The inner lining has a receiving space constructed by folding and stitching at least one waterproof fabric. Multiple seam lines on the inner lining are covered by waterproof tapes. The inner lining may prevent the rainwater permeating into the receiving space through the seam lines. Items may be protected from the wet in the receiving space of the inner lining. Further provided is a waterproof bag having the inner lining. The inner lining is sewed in an outer bag to construct the waterproof bag. Multiple seam lines between the outer bag and the inner lining are also covered by waterproof tapes. The inner lining and the waterproof bag having the inner lining provide more convenience and safety for users in rainy days.