In order to solve the calibration problem of the stereo vision sensor with large field-of-view (FOV), a novel calibration method using flexible target is proposed. According to the stereo vision sensors′ FOV, several small planar targets are combined by the rigid connection device. The flexible target is moved in front of the stereo vision sensor several times (at least two times) without restriction, and the transformation matrix between the two cameras is solved according to the invariance of the relative positions between small planar targets. The transformation matrix is optimized using the nonlinear optimization method. Experimental result shows that the accuracy of the proposed method is higher than that of a small target, and close to that of a large target.