In order to solve the problem that the time-frequency aggregation is not strong in the existing parameter estimation method and the estimation accuracy is low under low SNR

a parameter estimation method of frequency hopping signal based on quadratic iterative sparse reconstruction（QISR） is proposed.Firstly

sparse reconstruction is performed according to the time-frequency sparseness of the frequency-hopping signal

and the time-frequency distribution matrix of the signal is obtained.Then

by analyzing the characteristics of the time-frequency distribution matrix

the signal is subjected to quadratic iterative sparse reconstruction to obtain the quadratic time-frequency distribution matrix.In addition

in order to improve the performance of the algorithm at low SNR

binary morphological filtering is used for processing of the time-frequency diagram.Then good parameter estimation of the signal is achieved.The simulation results show that the proposed algorithm can effectively improve the precision of parameter estimation and has a good estimation effect under low SNR.