The embodiment of the invention provides a method and a device for controlling flash, and relates to the technical filed of digit. According to the method and the device, a corresponding supplementary light driving current and an exposure driving current can be set according to the difference of statistical gray values of a preview picture, the balance of preliminary flash, flash and ambient light is ensured, and the quality of shot pictures is increased as well. The method comprises the following steps of obtaining the statistical gray values of the preview picture, searching corresponding supplementary light parameters in a preset dynamic supplementary light list according to the statistical gray values of the preview picture if the statistical gray values of the preview picture are less than a preset threshold, setting the supplementary light driving current according the supplementary light parameters, driving a flashlight to carry out the preliminary flash by the supplementary light driving current, searching corresponding exposure driving current in a preset exposure parameter list according to the supplementary light parameters, and driving the flashlight to carry out the flash by the exposure driving current.