The invention provides a full-automatic measuring method for a three-dimensional (3D) manikin, characterized by comprising the following steps: carrying out the 3D anthropometric scanning of a human body to obtain a 3D manikin comprising triangles; automatically searching human body mark points and automatically sectioning the human body; and automatically measuring the size of the human body. The invention has the advantages that the 3D scanned manikin is fully automatically marked and measured under the condition of lacking manual intervention, greatly increases the measuring speed of 3D human body data and has higher measuring accuracy.