  We present firstly the equation of motion for a test scalar particle coupling
to Einstein tensor in the Schwarzschild-Melvin black hole spacetime through the
short-wave approximation. Through analysing Poincar\'{e} sections, the power
spectrum, the fast Lyapunov exponent indicator and the bifurcation diagram, we
investigate the effects of coupling parameter on the chaotic behavior of the
particles. With the increase of the coupling strength, we find that the motion
of coupled particle for the chosen parameters becomes more regular and order
for the negative couple constant. While, for the positive one, the motion of
coupled particles first undergoes a series of transitions between chaotic
motion and regular motion and then falls into horizon or escapes to spatial
infinite. Our results show that the coupling brings about richer effects for
the motion of the particles.
