A method and apparatus for converting into white light under laser excitation, and specific applications of the method and the apparatus in the field of lighting. The method comprises exciting a light conversion medium (1) by means of blue laser and then converting the blue laser to obtain white light. The light wavelength of the blue laser falls within the range of 420-470 nm. The blue laser may be directly generated by an LD chip, and may also be generated by means of optical fiber combination after a plurality of LD chips are connected in series, in parallel, or in a series-parallel hybrid mode, or generated by a currently single LD light source or an LD light source array, or generated by means of frequency doubling or frequency mixing by a pump light source after gaining; or the blue laser is a blue laser having a wavelength of 420-470 nm generated by other approaches. The light conversion medium may be any one of glass, transparent ceramics, and a single crystal.