The invention provides a solar and air energy water heater control system and a solar and air energy water heater control method. By reasonably setting a delta t value, a solar energy heat collectionplate surface temperature probe continuously senses the surface temperature of a solar energy heat collection plate for three times, so that whether the solar energy heat collection plate can fully supply heat to a thermal insulation water tank is judged more precisely. A water temperature and a water tank liquid level value in the thermal insulation water tank are sensed by a water tank temperature probe and a water tank liquid level sensor correspondingly, the water discharge temperature, the water discharge time and the water discharge flow rate of the thermal insulation water tank every time are further sensed through a water discharge temperature probe, a water discharge timer and a water discharge flowmeter correspondingly, and a solar and air energy heat pump water heater preferablyadopts the solar energy heat collection plate to collect heat, and, after judging whether the heating load of the solar energy heat collection plate can meet the user requirement, determines a start-stop state and the available machine time of an air energy heat pump unit, so that a user can start the air energy heat pump unit in a low electricity price time period and a heat pump high energy efficiency ratio time period according to the demands, and energy-saving control is achieved.