  We study the orbital angular momentum structure of the quarks inside the
proton. By employing the light-cone diquark model and the overlap
representation formalism, we calculate the chiral-even generalized parton
distribution functions (GPDs) $H_q(x,\xi,\Delta^2)$,
$\widetilde{H}_q(x,\xi,\Delta^2)$ and $E_q(x,\xi,\Delta^2)$ at zero skewedness
for $q=u$ and $d$ quarks. In our model $E_u$ and $E_d$ have opposite sign with
similar size. Those GPDs are applied to calculate the orbital angular momentum
(OAM) distributions, showing that $L_u(x)$ is positive, while $L_d(x)$ is
consistent with zero compared with $L_u(x)$. We introduce the impact parameter
dependence of the quark OAM distribution. It describes the position space
distribution of the quark orbital angular momentum at given $x$. We found that
the impact parameter dependence of the quark OAM distribution is axially
symmetric in the light-cone diquark model.
