The conventional method to determine the cosmic curvature is to measure the total mass density \Omega _ { tot } .
Unfortunately the observational \Omega _ { tot } is closely near the critical value 1 .
The computation of this paper shows that \Omega _ { tot } \approx 1 is an inevitable result for the young universe independent of the spatial topology .
So the mass density is not a good 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 .

PACS numbers : 98.80.-k , 98.65.-r , 98.80.Es , 98.80.Jk

Key Words : cosmic curvature , large scale structure , galactic distribution , galaxy count