Camera calibration is one of the key technologies to computer vision. According to problems rom presently calibration technology such as complicated calculation process and inconvenient calibration targets usage, a self-calibration method for binocular cameras is proposed. Calibration process can be performed when there are two groups of orthogonal parallel line in scene. A calibration equation is built according to constraint relations among vanishing points forming in the image planes. So the intrinsic and extrinsic parameters of cameras are calculated. And structure parameters of a binocular camera are calibrated incorporating with the principle of binocular stereo vision. Comparison experiments are performed to presently laboratory equipments by the method. Experimental results show that the method is easy, effective and can be used in many fields such as research on machine vision and 3D reconstruction.