A white balance adjusting method with scene detection comprises: receiving source image data corresponding to a plurality of sensing units; generating an initial white balance gain according to the source image data; generating an image parameter corresponding to a plurality of parameter elements according to the source image data; determining whether a preset condition is satisfied according to the image parameter to generate a decision result; determining whether the source image data are associated with any of built-in scenes according to the decision result in which the built-in scenes include a first scene in connection with a first-scene adjustment rule; and if the source image data are associated with the first scene, adjusting the initial white balance gain or processing the source image data according to the first-scene adjustment rule to thereby obtain a scenic white balance gain and adjust the source image data with it.