A method and an apparatus for generating depth information are provided. A main depth map associated with one of a left image and a right image and corresponding to multiple first pixels is obtained. The left image or the right image associated with the main depth map is divided into multiple segments according to pixel information, so as to obtain a segment distribution map including the segments. Multiple invalid depth values which do not match to a reliable condition are removed from the main depth map according to the segment distribution map, so as to generate a necessary repair depth map including multiple holes. Multiple optimized depth values are respectively generated for the holes in the necessary repair depth map according to the segment distribution map, and the optimized depth values are filled into the necessary repair depth map to generate an optimized depth map.