A convention is a large meeting to pursue some particular purposes by means of social interactions between participants. Therefore, the key to decide whether a convention is successful or not is that how many active people participate in a meeting. Revenues of this sort of convention depend on a registration fee of participants, so that it is possible to influence badly on a budget operation according to the fact that the number of real participants is smaller than the number of prospective participants. In conclusion, in order to have a large attendance convention organizers and managers should announce benefits by positive attitudes when participants attend a meeting. Representative methods of promotion for providing prospective participants with convention information are advertisements, P.R activities, and personal sales.