A light source control method and a light source control device are used for controlling a light source. The light source control device includes a position detecting sensor and a microcontroller. The light source control method includes steps of generating a first signal according to an object touching a position of the position detecting sensor, and generating a control signal according to a light source adjustable parameter set corresponding to the first signal for controlling an illuminating status of the light source. The light source adjustable parameter set includes a plurality of color value components. The control signal is generated by the microcontroller according to the color value components.