When measuring a complex surface, the probe must move gradually in the opposite direction of the normal vector of the surface to touch the work-piece surface and measure the actual spatial position of the measuring point. However, the triangular mesh is unavailable to obtain the normal vector directly and the normal vector of the corresponding facet will be used instead. This paper proposes a direct retrieving facet method of measuring the complex mesh surface. Through the operation of facet data acquisition, vector cross product calculation and selected facet judgement, the corresponding facet of the measuring point can be directly retrieved and the normal vector of the facet can be used to drive the movement of the probe for accuracy detection. Finally, the proposed method is programed and verified in IDEL by some test data. This method will be valuable for the high-speed precision detection and can be used for the complete development of the complex mesh surface measuring system.