Aiming at the problem of blind PN code estimation of long period code Direct Sequence Spread Spectrum (DSSS) signals,a spread spectrum code estimation method based on improved Genetic Algorithm (GA) is proposed.Firstly,the GA is improved by initializing the population with observation signals,retaining the optimal individuals and adding some randomly generated individuals to prevent local optimization.Then,the synchronization point of PN code and information code is estimated according to the spectral norm of signal covariance matrix.Finally,a period of observation signal is intercepted,and the improved GA is used to estimate the PN code.The simulation results show that the improved algorithm speeds up the convergence process,reduces the number of iterations,and achieves good results under the condition of low SNR.