To acquire projectile body pitch and roll parameters on real-time, put forward a new projectile body attitude method, using to obtain geomagnetic field intensity and combine microcomputer gyroscope. Firstly, the principles of attitude measurement system and hardware design based on geomagnetic field distribution are introduced. Secondly, the various error factor and influence are analyzed, and the relevant to compensation methods are put forward. Finally, testing and verification for the designed system is curried out. The experiment results show that attitude measurement accuracy is better than 1°.