Abstract: According to the characteristics of flight data，a novel combined method in missing flight data complement is proposed.This method combines the advantages of the B-spline curve fitting and Least Squares Support Vector Machines（LSSVM），and processes the results of single method with weighted mean.The reliability of the method is strengthened，and the precision in flight data complement is enhanced with the combined method.The contrastive experiment results show the feasibility and applicability of the combined method.