The invention discloses an automatic positioning and proportion determining method for proportion of a human face. A complete human face is automatically detected and extracted from a high-definition human face image. Partial characteristics are automatically detected and characteristic points are positioned. The detected partial characteristics comprise a left eye, a right eye, a left eyebrow, a right eyebrow, a nose, a mouth, a forehead hair line area, a chin area and a face width area. The positioned characteristic points comprise a left eye inner canthus point, a left eye outer canthus point, a right eye inner canthus point, a right eye outer canthus point, a left eyebrow point, a right eyebrow point, a nose lower point, a chin point, a forehead hair line point, a left eye outer canthus outside hair line point and a right eye outer canthus outside hair line point. Finally, pixel spaces and proportion relationships among the proportion are automatically calculated according to the coordinate positions of the characteristic points in the human face image. The method according to the invention has advantages of: visible positioning result, visible calculating result, and high accuracy.