  The eigenvalue problem of stochastic Hamiltonian systems with boundary
conditions was studied by Peng \cite{peng} in 2000. For one-dimensional case,
denoting by $\{\lambda_n\}_{n=1}^{\infty}$ all the eigenvalues of such an
eigenvalue problem, Peng proved that $\lambda_n\to +\infty$. In this short
note, we prove that the growth order of $\lambda_n$ is the same as $n^2$ as
$n\to +\infty$. Apart from the interesting of its own, by this result, the
statistic period of solutions of FBSDEs can be estimated directly by
corresponding coefficients and time duration.
