An efficient method for enhancement of high harmonics spectrum and single attosecond pulses generation is presented in femtosecond laser interaction by a typical atom. In this method the genetic algorithm was used for optimization, and physical constraints were introduced properly in this approach. For illustration, the interaction of laser pulses by ionized helium atom in 1D model is considered. It is shown by using proper cost function the spectrum of high harmonics can be improved and results into single and more intense attosecond pulses.