Abstract: In algorithm for estimation of LFM signal parameter,the Discrete Polynomial Phase Transform(DPT) method is a common method.However,the method is not suitable for engineering application due to limited range of signal parameter esimation.Therefore,based on the method of Iterative Linear Prediction(ILP),modified method of range of signal parameter estimation is proposed.On the condition of ensuring estimation precision,this method can greatly improve the range of estimation.First,the theory of ILP measurement frequency was presented,then the modification idea and the realization approach of the range of signal parameter estimation is proposed.Finally,simulation demonstrated the effectiveness of this method.