Abstract: This paper presents a novel approach for depth and motion estimation,aiming at the model-based pose estimation problem.The estimation procedure consists of two steps.Firstly,it estimates the rotational matrix according to three point pairs constituted by three model points.Then,the translation vector and depths are computed from one of the three pairs.In order to enhance the precision of the estimated results,a simple and effective optimization algorithm is also proposed.The main advantages of this method are that it estimates the rotational matrix individually and can obtain good estimation results according to small number of model points.Experiments performed on synthetic data and real images demonstrate the effectiveness of this approach.