Provided is a control method for controlling an imaging device. The control method includes operations that: a cached image output by an imaging device is processed to identify whether there is an overexposed area (S10); in a case where there is the overexposed area, an RGB channel value of a surrounding area around the overexposed area is acquired (S20); and white balance processing is performed on the cached image according to the RGB channel value (S30). Further provided are a control device, a mobile terminal and a computer-readable storage medium.