  The dynamics of opinion is a complex and interesting process, especially for
the systems with large number individuals. It is usually hard to describe the
evolutionary features of these systems. In this paper, we study the self
excitation opinion model, which has been shown the superior performance in
learning and predicting opinions. We study the asymptotic behaviors of this
model for large number of individuals, and prove that the asymptotic behaviors
of the model in which the interaction is a multivariate self excitation process
with exponential function weight, can be described by a Mckean-Vlasov type
integro differential equation. The coupling between this equation and the
initial distribution captures the influence of self excitation process, which
decribes the mutually- exicting and recurrent nature of individuals. Finally we
show that the steady state distribution is a "contraction" of the initial
distribution in the linear interaction cases.
