A new calibration method using monocular vision is proposed to calibrate the dot structured light measurement system. Let the laser rangefinder circle around the rotation axis and use two planes to intercept laser beam respectively in order to form the laser spot. Three-dimensional coordinates of the laser spot is obtained by monocular vision, the virtual output light spot of laser rangefinder is got by calculating the difference of the two laser spots. Direction vector of the rotation axis is fitted and point coordinate in the rotation axis is fixed. The use of virtual output light spot in the calibration improves the accuracy of rotation axis, so the rotation axis at any position can be calculated easily. The three-dimensional coordinates of target can be calculated by dot structured light measurement system though accurately calibrating the two axes of the turntable. The experiments show that the measuring precision of the system is within 0.5 mm at present, this calibration method is simple, reliable and can be used in other measuring system with a turntable.