The genetic algorithm with the elitist strategy is applied for the design of dual-frequency equal-splitting Wilkinson power divider. It is composed of a two-section transmission line transformer and two isolation resisters. After even and odd mode analysis with ideal transmission-line model, the optimal parameters are obtained by genetic algorithm, crossover and mutation of changing probability are used to prevent premature and rapid convergence in genetic algorithm, so as to get the optimized results rapidly and efficiently. The performance of the power divider is also simulated with ADS. The result shows that impedance is matched at all ports and isolation between the two output ports is more than 40 dB. This method can be used to practical design.