A new three-dimensional (3D) profile measuring method which combines the atomic force microscopic (AFM) probe with the position sensitive detector (PSD) range probe is proposed. This method can obtain both the large size 3D profile and micro morphological character of a point on the sample. A dual-probe 3D profile measuring system is developed. The working principle is elaborated and the three parts of the system, the dual-probe, the step-controlled scanning stage and the computer controlling center are illuminated. The measuring range of the system is demarcated by measuring a known grating of 2000 line/mm. The 3D surface profile images in local morphology and entire profile of an annular gasket with inside and external diameter of 4 mm and 8 mm are given respectively. The experimental results show that this system is expected to be utilized both in large range measurement and local three-dimensional reconstruction with high-precision for samples which are of different sizes and materials.