Using the market clearing model for Taiwan's broiler industry, the purpose of this study is to evaluate the impact of Avian Influenza breaking out on the incremental cost from vaccines control, smuggling amount, smuggling investigation rate, and broiler product weight, by simulating the social welfare changing under above four scenarios. The empirical finding indicates that government would enormously increase the vaccines inputs while facing the Avian Influenza hits, which causes the average farm price of broiler to decease by 0.0717% and also to decrease gradually the changing rate of retail price in turn. Finally, the result simulating the larger scale of terminating the infected poultry presents that social welfare increases NT$ 10.64 billion during the period of implementing vaccines control. Compared the condition with no termination action, the social welfare significantly enhances NT$ 15.02 billion. This implied that the termination action on the infected poultry substantially leads to positive benefits on overall social welfare.