Considering the motion parameter estimation problem for a high.speed maneuvering target with complex motions, a novel motion parameter estimation algorithm based on the Robust Cross-Correlation Function(RCCF) and Polynomial Chirplet Transform(PCT), i. e., RCCF-PCT, is proposed. Firstly, after range profile image enhancement using the power-law transformation, the cross-correlation and robust polynomial regression operations are adopted to measure the target's motion parameters, which are used for the preliminary correction of the Range Migration(RM). Then, it employs the PCT to obtain the parameterized Time.Frequency Representation(TFR) of the Doppler Frequency Migration(DFM) coarsely compensated signal, and estimates the residual motion parameters with the time .frequency ridge feature extracted from the TFR. Finally, several numerical experiments are presented to demonstrate the effectiveness.