  The influence of the rotation on the total masses and radii of the neutron
stars are calculated by the Hartle's slow rotation formalism, while the
equation of state is considered in a relativistic $\sigma-\omega$ model.
Comparing with the observation, the calculating result shows that the double
neutron star binaries are more like hyperon stars and the neutron stars of
X-ray binaries are more like traditional neutron stars. As the changes of the
mass and radius to a real neutron star caused by the rotation are very small
comparing with the total mass and radius, one can see that Hartle's approximate
method is rational to deal with the rotating neutron stars. If three property
values: mass, radius and period are observed to the same neutron star, then the
EOS of this neutron star could be decided entirely.
