A calibration method of binocular stereo measurement system is proposed based on calibration cross. The intrinsic parameters of the two cameras are calculated precisely and the three-dimensional (3D) target point sets are reconstructed in each camera coordinate system respectively by using the multiple-view geometrical constraint and a generic sparse bundle adjustment. Then the extrinsic parameters are calculated by using the rigid-body transform of the two 3D point sets. This method is simple and flexible for field operation because it only needs the calibration cross to be photographed by two cameras simultaneously once and then separately several times. Based on a binocular stereo measurement system calibrated by the proposed method, a staff gauge of 611.800 mm long is measured many times. The result shows that the average measurement value is 611.776 mm, and standard deviation is 0.030 mm.