A non-intrusive precise measuring method for complex surface in size of tens of meters whose normal vector varies greatly is presented. Global control points and measured points are set by means of optical projection. Orientation camera and orientation target fixed on measuring camera are used to solve estimation problem of measuring camera′s initial position and posture. Then the three-dimensional coordinates of measured points are retrieved based on ray bundle adjustment technique. It overcomes the limitation of existing methods that coding targets must be set on measured surface, so it can accomplish non-intrusive measurement. Experimental results show that the total root mean square (RMS) error is 0.07 mm, therefore, the principle of method is reasonable and can solve problems with high accuracy and efficiency.