  From the Main galaxy sample of the Sloan Digital Sky Survey Data Release 6
(SDSS DR6), we construct two volume-limited samples above and below the value
of M, to explore the difference of the environmental dependence of galaxy
properties between galaxies above and below the value of M . We measure the
local three-dimensional galaxy density in a comoving sphere with a radius of
the distance to the 5th nearest galaxy for each galaxy, and compare basic
properties of galaxies in the lowest density regime with those of galaxies in
the densest regime. It is found that the galaxy luminosity strongly depend on
local environments only for galaxies above M, but this dependence is very weak
for galaxies below M . It is worth noting that g-r color, concentration index
ci and galaxy morphologies strongly depend on local environments for all
galaxies with different luminosities. This shows that M is an characteristic
parameter only for the environmental dependence of galaxy luminosity.
