  In this paper, we present a new hydrostatic equilibrium equation related to
dilaton gravity. We consider a spherical symmetric metric to obtain the
hydrostatic equilibrium equation of stars in $4$-dimensions, and generalize TOV
equation to the case of regarding a dilaton field. Then, we calculate the
structure properties of neutron star using our obtained hydrostatic equilibrium
equation employing the modern equations of state of neutron star matter derived
from microscopic calculations. We show that the maximum mass of neutron star
depends on the parameters of dilaton field and cosmological constant. In other
words, by setting the parameters of new hydrostatic equilibrium equation, we
calculate the maximum mass of neutron star.
