The present disclosure provides a camera calibration method and a system thereof. The method includes setting up a camera in a space; establishing or selecting two line segments in the space, and obtaining an image of the space including the two line segments, and obtaining heights and image coordinates of upper and lower endpoints of the two line segments; calculating a focal length, a first rotation angle, a second rotation angle and a third element of a translation vector of the camera based on the information of the two line segments; calculating a third rotation angle of the camera based on a reference direction and the camera information obtained above; calculating a first element and a second element of the translation vector of the camera based on a reference point and the camera information obtained above.