A heating method and device for a variable frequency heat pump water heater, and a variable frequency heat pump water heater. The method includes: matching the current time according to the correspondence between the historical noise value of the environment within the preset range of the variable frequency heat pump water heater unit and the preset time period Corresponding historical noise value; adjust the current heating frequency according to the positive correlation between the historical noise value and the heating frequency and the matched historical noise value; heat according to the adjusted current heating frequency. Through the present invention, the advantage of adjustable frequency of the variable frequency heat pump water heater can be effectively used. By controlling the heating frequency of the unit, the high-frequency heating work of the unit can be realized when the ambient noise itself is relatively large, and the ambient noise is relatively small. At the same time, low-frequency heating work is carried out to effectively reduce the impact of the noise generated by the variable-frequency heat pump water heater on the surrounding environment.