In order to reduce the geomagnetic goniometer measured magnetic field vector information solver projectile rolling attitude angle error, Kalman filtering algorithm was used to estimate the projectile rolling angle in this article. Through the analysis of the change rule of rolling angular velocity, the second order approximate expression of rolling movement law of the elastomer was used as system equations of the Kalman filtering algorithm, and the nonlinear relationship between the strength of the magnetic field and the digital output was used as the measurement model of the kalman filtering algorithm. The simulation results showed that the precision of rolling angle and rolling angular velocity obtained by filtering met the requirement of trajectory correction projectile, which could be used to control the trajectory of the trajectory correction ammunition passive segment. Keywords: geomagnetic goniometer; Kalman filtering algorithm: projectile rolling angle measurement