  We determine relative stellar ages and metallicities mainly for about 80
elliptical galaxies in low and high density environments via the latest binary
stellar population (BSP) synthesis model and test a latest hierarchical
formation model of elliptical galaxies which adopted the new $\Lambda$CDM
cosmology for the first time. The stellar ages and metallicities of galaxies
are estimated from two high-quality published spectra line indices, i.e.
H$\beta$ and [MgFe]. The results show that elliptical galaxies have stellar
populations older than 3.9 Gyr and more metal rich than 0.02. Most of our
results are in agreement with predictions of the model: First, elliptical
galaxies in denser environment are redder and have older populations than field
galaxies. Second, elliptical galaxies with more massive stellar components are
redder while have older and more metal rich populations than less massive ones.
Third, the most massive galaxies are shown to have the oldest and most metal
rich stars. However, some of our results are found to be different with
predictions of the galaxy formation model, i.e. the metallicity distributions
of low- and high-density elliptical galaxies and the relations relating to
cluster-centric distance.
