The invention discloses an expression synthesis method and device based on phoneme driving and a computer storage medium, and the method mainly comprises the steps: recognizing a target voice text according to a preset
database, so as to obtain a phoneme sequence, and converting the phoneme sequence into a replacement expression parameter sequence; extracting to-be-replaced original sub-video datafrom the original video data based on the voice duration of the target voice text; constructing a three-dimensional
face model based on faces in the original sub-video data, extracting to-be-replacedexpression parameters of the three-dimensional
face model frame by frame to generate a to-be-replaced expression parameter sequence, and replacing the to-be-replaced expression parameter sequence with the replaced expression parameter sequence; utilizing the replacement expression parameter sequence to drive a three-dimensional
face model to generate a target two-dimensional
image sequence, and rendering the target two-dimensional
image sequence frame by frame; and splicing the rendered target two-dimensional
image sequence to generate target sub-video data for replacing the original sub-video data. According to the invention, the expression synthesis video with a more real effect can be efficiently and accurately obtained.