The invention discloses an all-weather solar energy and sewage energy mixed auxiliary heat pump water heater system. The system can furthest utilize solar energy and sewage energy, reduce the utilization of high-grade energy sources, and effectively solve the problem of frosting of a heat pump in winter and has the characteristics of great energy-saving effect, all-weather hot water supply, all-weather heat supply and refrigeration and the like. Not only can water for flushing the toilet and irrigating domestic green plants be saved by collecting domestic miscellaneous sewage, but also abundant cold energy and heat energy contained in the domestic miscellaneous sewage can be effectively utilized, the refrigeration and heating efficiency of the heat pump is increased, and the frosting of the heat pump in winter can be effectively solved. The system can complete the functions of hot water supply, heating and refrigeration of the traditional solar water heater and the heat pump, and saves more energy and can be better adapted to weather change as compared with the traditional solar water heater and the heat pump system.