A method and apparatus for modulating a particular light source used for laser display are provided. The apparatus includes a digital modulator digitally modulating light output from a semiconductor laser to a frequency higher than a repetition frequency required for laser image display; and a pixel brightness adjustor inserting at least one high-speed pulse into a period of the modulated output light, which is required for a single pixel, and adjusting a brightness of the pixel by adjusting the number of the inserted high-speed pulses.