Abstract: Aim To study attitude measurement method of flight body and attitude measurement principle of the earth magnetic field sensor. To set up the attitude detecting maths model of the earth magnetic field sensor, and propose the flight body attitude calculating method.Methods\ According to Faraday electromagnetism induction law, i.e. when a wire loop incises the magnetic force line of the earth magnetic field, it will bring about the induction electromotive force, an attitude measurement system was designed based on the earth magnetic field sensor. Results An earth magnetic field sensor and attitude measuring system were designed, and experiment data were analyzed and processed. It was proved that the rotating speed measurement error is 0 05 r/s. Conclusion\ This earth magnetic field sensor can be used to detect attitude of high load rotating flight body.