The invention relates to a square root cubature Kalman filter-based aircraft attitude estimation method which comprises the steps of setting an initial value and a Rodriguez parameter when calculating time updating, calculating a volume point value, calculating a quaternion error point, calculating a quaternion volume point, calculating an iteration quaternion and an iteration quaternion error, calculating an iteration volume point, estimating a one-step prediction state, estimating a square root factor prediction error covariance matrix, calculating a volume point in measurement updating, calculating an iteration volume point value, calculating prediction measurement estimation, calculating square root factor innovation covariance matrix estimation, calculating a cross covariance matrix, carrying out Kalman gain, estimating state updating, calculating an estimated error covariance matrix and a corresponding square root factor, updating the quaternion, and calculating a corresponding estimated error euler angle. According to the square root cubature Kalman filter-based aircraft attitude estimation method, the precision and the stability of aircraft attitude can be improved.