A practicable method of determining the camera′s intrinsic parameters(with 5 parameters) as well as its extrinsic parameters is proposed.All the camera parameters are determined based on the walking humans and their shadows and the method is linearly.Meanwhile the relationship of the corresponding points have not to be considered,so the speed of calibration could be increased greatly.Extensive simulations and experimental results with real images show that this proposed method is both accurate and robust.This method can be used in on-line system.