  We investigate the accumulated wealth distribution by adopting evolutionary
games taking place on scale-free networks. The system self-organizes to a
critical Pareto distribution (1897) of wealth $P(m)\sim m^{-(v+1)}$ with $1.6 <
v <2.0$ (which is in agreement with that of U.S. or Japan). Particularly, the
agent's personal wealth is proportional to its number of contacts
(connectivity), and this leads to the phenomenon that the rich gets richer and
the poor gets relatively poorer, which is consistent with the Matthew Effect
present in society, economy, science and so on. Though our model is simple, it
provides a good representation of cooperation and profit accumulation behavior
in economy, and it combines the network theory with econophysics.
