Aiming at the sceneswhere contact rotation angle measurement devices such as decoding device are not applicable, apure attitude measurement algorithm based on monocular visual odometer is designed, which possesses the advantages of low cost, good precision and no drift. In order to solve the application problem in pure rotation condition,based on the classical monocular visual odometer algorithm,adopting the methods of assuming depth, direct initialization, modifying attitude calculation and optimizing algorithm, the problem that the camera cannot workin pure rotation condition is solved. Aiming at the practical problem that the camera cannot be accurately installed on the rotation center of the measured object, an installation bias model is established and the attitude measurement algorithm is improved, which effectively solve the installation bias problem. Meanwhile, an offline measurement schemeis proposed,with which the installation bias parameter identification is achieved. The effectiveness of the algorithm was verified with a highprecision twoaxis turntable. The experiment results show that the proposed algorithm still possesses good comprehensive performance even using lowcost cameras. The multidegreeoffreedom dynamic angle measurement error is within 05 degree.