The conventional method to determine the cosmic curvature is to measure the total mass density
. Unfortunately the observational
is closely near the critical value 1. The computation of this paper shows that
is an inevitable result for the young universe independent of the spatial topology. So the mass density is not a good
... [Show full abstract] criterion to determine the cosmic curvature. In this paper, we derive a new criterion based on the galactic distribution with respect to redshift z, which only depends on the cosmological principle and geometry. The different type of spatial topology will give different results, then the case can be definitely determined.