  Within the framework of Dyson-Schwinger equations and by means of Multiple
Reflection Expansion, we study the finite volume effects on the chiral phase
transition in a sphere, especially discuss its influence on the location of the
possible critical end point (CEP). According to our calculations, when we take
the sphere instead of cube as a research, the influence of finite volume
effects on phase transition is not as significant as previously calculated. For
instance, as the radius of spherical volume decreases from infinite to $2
\mathrm{fm}$, at zero chemical potential and finite temperature, the critical
temperature $T_{c}$ has only a slight drop. And at finite chemical potential
and finite temperature, the location of CEP shifts toward smaller temperature
and higher chemical potential, but the amplitude of variation does not exceed
$20\%$. So we find that not only the size of the volume, but also the shape of
the volume will have a considerable impact on the phase transition.
