A new method for camera calibration is proposed by utilizing a T-shaped target of two orthogonal one-dimensional (1D) objects. Through this method, only one projected image of 5 points with known coordinates on the T-shaped target is needed. Then according to the flexible target principle, 4 collinear points composed by the virtual and marked points can be determined, and finally the first-order radial distortion parameters of the lens are calibrated through the primality, associativity and cross-ratio invariability of the projective transformation. Using the calibrated distortion parameters to correct the image distortions, it is possible to calibrate the intrinsic and extrinsic parameters of the camera on the basis of coordinate transformation of the two orthogonal 1D objects. This method, using the linear solution to gain the distortion parameters of the lens, is able to prevent the parameters coupling in the nonlinear iterative optimization process in traditional methods. Experiments prove that if the distortion correction of the camera lens is not conducted, the camera calibration result will be unstable with the increase of image noises; while after conducting the distortion correction, a stable calibration result with high precision will be ensured when the initial values of a simple calibration are optimized. The calibration experiment is simple and easy to operate. Only one image is needed in realizing the calibration of the camera lens distortion and of the intrinsic and extrinsic parameters, thus the real-time operation can be realized.