To improve the measurement accuracy of curvature radius， a method of detecting divided aperture laser differential confocal radius measurement was proposed. In this study， the principle of this new measurement and the algorithm of virtual pinhole positioning were explored. The detection light path of the confocal measurement system was blocked by a D-type aperture such that half of the measurement beam was focused on the focal plane detection charge-coupled device （CCD）. The Airy disk detected by the CCD was divided into focal spot differential subtraction normalized detection using the virtual pinhole positioning algorithm. Then， the zero point of the differential confocal curve was used to accurately determine the focus of the "confocal" position and the "cat's eye" position of the test lens， measuring the distance between them. Finally， a high-precision measurement of the radius of curvature was achieved. Experiments and analysis show that the radius of curvature measured by this method is -121.209 4 mm， with a repeatability better than 5×10^-6， without the need to adjust the hardware according to the parameters of the measuring objective and tested lenses. This meets the requirements for high-precision measurement of the radius of curvature and simplifies the optical path structure， reducing the structure and adjustment costs and providing a new method for rapid and high-precision measurements of the radius of curvature.