Abstract: A knapsack with padded back includes a knapsack main body defining at least one receiving space, at least one shoulder strap connected to a back of the knapsack main body, and a pad attached to at least an outer side of the back of the knapsack main body. The pad consists of an inner watertight layer in contact with the back of the main body, a middle air-permeable elastic layer, and an outer cover layer connected along an outer periphery to a boundary of the back of the main body. The middle air-permeable elastic layer is made of a thermoplastic elastic material and formed with a plurality of voids to provide the pad with good cushioning and air convection effects, making the knapsack with padded back more comfortable for carrying.