The embodiments of the present invention relate to a voice enhancement method and device. The voice enhancement method includes: acquiring M first linear prediction coefficients of a voiced sound frame signal, wherein M is the order of a linear prediction filter; acquiring a raising factor, wherein the raising factor is obtained according to the relevance among the frequencies in the short-time spectrum envelope corresponding to the M first linear prediction coefficients; modifying the M first linear prediction coefficients according to the relevance between the raising factor and the M first linear prediction coefficients so that the formant energy of a second short-time spectrum envelope corresponding to M second linear prediction coefficients obtained after modification is enhanced and the medium-high frequency spectrum components thereof are compensated to a certain extent as compared to the first short-time spectrum envelope corresponding to the M first linear prediction coefficients. Given the determining effect of the formant energy on the tone quality of the voice and the contribution to the sentence intelligibility of the voice by the medium-high frequency spectrum components of the voice, after the processing of the method in the embodiments of the present invention, the quality of and intelligibility of the voice are improved together.