  The ground state properties of He isotopes are studied in the nonlinear
relativistic mean-field (RMF) theory with force parameters NL-SH and TM2. The
modified Glauber model as a gatekeeper is introduced to check the calculations.
The investigation shows that the RMF theory provides a good description on the
properties of He isotopes. The many-body space information of 4He + neutrons
are obtained reliably. As a product, the calculation gives a strong evidence
for neutron halo in 5He.
