Abstract: A method for controlling a compressed air supply device of a compressed air system of a utility vehicle. The compressed air supply device has a compressor, an air dryer unit and a regeneration valve device and being operated in an operating mode with delivery phases and regeneration phases. In the method, a current humidity, e.g. a relative or absolute humidity, is ascertained in the compressed air system, a current dew point depression (c-DPD) is ascertained from the ascertained humidity, a target dew point depression (t-DPD) is ascertained from current and/or projected ambient temperature data (T0, T(t)) and/or from current and/or projected vehicle operating data, and a target dew point depression (t-DPD) is subsequently ascertained from current and/or projected ambient temperature data (T0, T(t)) and compared with the current dew point depression (c-DPD). The operating mode and/or the regeneration phases are subsequently set and/or changed.