A method for making a bag with a window includes a step of making an outer surface which is composed of a first layer and a second layer glued to the first layer; a step of making a through hole through the outer surface; a step of making an inner surface which is composed of a high isolation layer and a plastic layer, and a step of connecting the second layer to the high isolation layer by way of non-liquid adhesive so as to form a bag with a window. The high isolation layer prevents air and moist from entering into the bag so as to keep freshness of the food received in the bag.