In this paper with the aim of analyses, different optimization algorithms including genetic algorithm (GA), particle swarm optimization (PSO), simulated anealing algorithm (SA) and intelligent water drop algorithm (IWD) are applied on the single and multi-port straight wire scatterers terminatted with nonlinear loads and their accuracies are evaluated. For simplicity, each scatterer is normally illuminated by an incident plane wave under single tone exciation. The simulation results show that among different optimization algorithms carried out up to now, the itelligent water drop algorithm (IWD) has the best accuracy and shortest run time in comparison with genetic algorithm (GA), partical swarm optimization (PSO) and simulated anealing (SA) algorithms.