  We investigate the circular motion and chaos bound of a charged particle near
4D charged AdS black holes in Einstein-Gauss-Bonnet gravity theory. By means of
the Jacobian matrix, the analytical form of the Lyapunov exponent of the
charged particle is constructed, which satisfies the upper bound when it is on
the event horizon. By further expanding the Lyapunov exponent near the horizon
and investigating a 4D charged Einstein-Gauss-Bonnet-AdS black hole with
different Gauss-Bonnet coupling constant, we find that it has some specific
values to determine whether a violation of chaos bound. Besides, we find that
in contrast to the static equilibrium, the circular motion of charged particle
can have a larger Lyapunov exponent due to the existence of angular momentum.
Moreover, we show that the black hole gets closer to the extremal state as the
Gauss-Bonnet coupling constant increases, and the bound is more easily
violated. In addition, the range of particle charge that may violate the
chaotic bound are found for different Gauss-Bonnet coupling constants. The
results show that as the GB coupling parameter increases, the value of particle
charge required to satisfy the violation of the chaos bound is even smaller.
