Heat exchanger of dish washing machine

The heat exchanger comprises a primary heat exchanger and a secondary heat exchanger, one end of the primary heat exchanger is provided with a waste discharge port in a communicated mode, the other end of the primary heat exchanger is provided with a waste water inlet in a communicated mode, and the position, close to the waste discharge port, of the upper portion of the primary heat exchanger is provided with a water inlet pipe in a communicated mode. A water inlet of the secondary heat exchanger is fixedly connected with a first water pipe, and a water outlet of the secondary heat exchanger is fixedly connected with a second water pipe. According to the utility model, waste hot water in the primary heat exchanger can be used for primarily heating tap water, and then hot air in the dish-washing machine is used for secondarily heating tap water in the secondary heat exchanger, so that the heating efficiency is higher, and more energy is saved compared with a single heat exchanger; waste hot water discharged a