In high-speed online visual measurement systems, it is difficult for small depth of field cameras to obtain clear images of calibration objects from different directions, resulting in the Zhang calibration algorithm having no solution or significant calculation errors. Therefore, a fast and accurate calibration algorithm for small depth of field cameras is proposed. Obtain a set of calibration object images located on the plane to be calibrated and parallel to it, linearly solve to obtain the height of the camera lens optical center to the plane to be calibrated, simplify the rotation matrix based on the camera posture, and finally use the calibration images located on the plane to calculate the camera′s internal and external parameters. The experimental results show that it is best to set the number of calibration image groups around 13, but using only one set of calibration images can also achieve high-precision calibration. In cases where the depth of field of the camera is small, this method has a root mean square error of less than 0.74 pixels for reprojection, and the calibration accuracy is improved by about 33% compared to Zhang′s calibration.