A video encoding method for an electronic device includes: dividing at least one CTU of a video image frame to acquire video prediction units of different sizes; performing initial selection on intra-predicted brightness prediction directions of the video prediction units according to a first rate-distortion-evaluation-function, to obtain a preset number of intra-predicted initially-selected brightness-directions of the video prediction units; performing fine selection on intra-predicted optimal brightness-directions of a related video prediction unit and intra-predicted initially-selected brightness-directions of a video prediction unit of a current size according to a second rate-distortion-evaluation-function, to obtain intra-predicted optimal brightness-directions of the video prediction unit; performing fine selection on intra-predicted chroma prediction directions of the video prediction units according to the second rate-distortion-evaluation-function, to obtain intra-predicted optimal chroma-directions of the video prediction units; and performing intra-prediction encoding on a current video encoding unit according to intra-predicted optimal brightness-directions and the intra-predicted optimal chroma-directions.