A method of disinfection and lighting by using LEDs and an LED device thereof are provided. Two kinds of LEDs, i.e., the lighting LEDs, and the UV-LEDs, are fixed on a circuit board evenly and mixedly in a certain way, and a separator is also provided on the circuit board. Meanwhile, a controlling circuit module having a function of mode switching controls the UV-LEDs and the lighting LEDs, in such a manner that the functions of UV-LED disinfection and LED lighting are combined well in a same device. The method replaces a conventional method of sterilization and disinfection using ultraviolet (UV) rays emitted by a low pressure mercury vapor lamp. After being treated with light distribution by the separator, directionality of light emitted by the LED is stronger, and the LED is easier to operate.