A flexible camera calibration technique using 2D-DLT and bundle adjustment with planar scenes is proposed in this paper. The equation of principal vertical line under image coordinate system represented by 2D-DLT parameters is worked out using the correspondence between collinearity equations and 2D-DLT. Proof of ambiguities in camera parameter decomposition with 2D-DLT parameters is given. Initial value of principal point can be obtained with at least two equations of principal vertical lines. Proof of critical motion sequences(CMS) is also given in detail. The practical decomposition algorithm of extrinsic parameters using initial values of principal point, focal length and 2D-DLT parameters is discussed elaborately. Planar-scene camera calibration algorithm with bundle adjustment(using collinearity equations) is addressed. For the proposed technique, either the camera or the planar pattern can be moved freely, and the motion need not be known. Very good results have been obtained with both computer simulations and real data calibration.