The invention relates to a weight and reference quaternion correction unscented quaternion estimation method, comprising: obtaining measurement data as quantity measurement through a gyro and a star sensor; establishing a quaternion-based discrete spacecraft nonlinear state space model; estimating an error quaternion, a gyro drift and a corresponding error covariance at a k moment by using an unscented quaternion estimator based on parameter and reference quaternion correction at a k−1 moment; and setting a filtering time as Ntime, if k