  It is believed that the production rate of $D^0\to K^0\bar K^0$ is almost
solely determined by final state interactions (FSI) and hence provides an ideal
place to test FSI models. Here we examine model calculations of the
contributions from s-channel resonance $f_J(1710)$ and t-channel exchange to
the FSI effects in $D^0\to K^0\bar K^0$. The contribution from s-channel
$f_0(1710)$ is sma$ For the t-channel FSI evaluation, we employ the
one-particle-exchange (OPE) model and Regge model respecti$ The results from
two methods are roughly consistent with each other and can reproduce the large
rate of $D^0\to K^0\bar K^0$ reasonably well$
