Abstract: The optimization design of novel combinatorial nonperiodic defected ground structures(CNPDGS) is accomplished applying artificial neural network(ANN) and Nelder-Mead simplex optimization algorithm.Compared with electromagnetic numerical analysis,regarding the ANN as analysis unit may bring great advantage in speed meanwhile the accuracy guaranteed.Therefore the ANN can take the place of FDTD as the calculational unit in the structure analysis.In the optimization design of the CNPDGS with the characteristic of dual stop band,dimensions that minimize the error function are obtained by simplex algorithm according to the desired parameters of transmission coefficient in the paper.The comparisons between computer simulation and experimentation demonstrate the effectiveness of the developed approach.