In this paper a new application of genetic algorithm (GA) in FIR filter design with frequency sampling method is presented.As the value of transition bands sample is obtained by GA,the problem that the value obtained by searching for table method is not the optimal can be solved.Suitable improvements are made for the standard GA in the paper.Two examples of lowpass and bandpass FIR filter design are provided.Experimental results have shown that the performance of the filter,which is designed via GA,is improved as compared with searching for table method.