Abstract: An efficient fixed-point smoothing method is presented in this paper, which is based on Miditch's and Rauch's fixed-point formulae. In the new algorithm, the multiplications of two n X n matrices are avoided and the computations of the filter for present smoother is simplified greatly. The results of computation analysis show that the efficiency of present method is more than 2 times as fast as that of Midtch's method. For its application, a new aircraft motion equation is given and accuracy of aerodymamic coefficient identification can be obtained by using the outputs carried out by the present algorithm.