This research is to define and develop the Pandemic Influenza simulation program. There are 3 parameters to determine whether a virus is potentially dangerous or not: (1) infectivity (2) virulence and (3) contagiousness. Avian Influenza has characteristics as follows: relatively high infectivity, high virulence and low contagiousness. On the other hand, Swine Influenza has characteristics as follows: relatively high infectivity, low virulence and high contagiousness. Pandemic Influenza happens because of these 3 parameters changes: increment of infectivity; virulence and contagiousness. These changes can trigger the Pandemic Influenza to become more infectious, spread faster within wider location.