Color temperature adjusting method and illuminating device using the method

A color temperature adjusting method comprising steps:

• providing a controller storing a color temperature setting value therein, a main white light source comprising a first sub-main white light source and a second sub-main white light source having a color temperature different from that of the first sub-main white light source, and an adjusting light source comprising a red light source, a green light source and a blue light source;
• comparing the color temperature setting value with that of a environmental light to obtain a difference value;
• controlling brightness of each of the first and second sub-main white light sources, the red light source, the green light source and the blue light source according to the difference value to obtain a compensation light;
• and
• mixing the compensation light with the environmental light to obtain a resulted light which has a color temperature equal to the color temperature setting value stored in the controller.