The invention relates to a method for controlling a water heater adaptable to gas with various heat values. The method includes that the water heater invokes matched parameters according to air pressure values and gas source types selected by a user to enable proportional valve current and fan rotating speed to work according to corresponding parameters; after the water heater is powered on, the user selects to enable the water heater to enter a setting mode; the user selects modes corresponding to altitude at which the water heater is positioned and the gas source types from a first working mode to an nth working mode; the water heater invokes working parameters corresponding to the selected working modes; after program recognition and automatic memory, the user enables the water heater to exit the setting mode; the water heater enters a working procedure, proportional valve current and fan rotating speed of the water heater work according to corresponding parameters. From the first working mode to the nth working mode, values of proportional valve current and fan rotating speed sequentially change according to rule changes. Consequently, the control process that the user selects manually and the water heater automatically matches parameters is realized, and misjudgment of the water heater is reduced greatly.