Theorem 1 Let X be a nonempty countable set, K={<X,d>: <X, d> is a discrete metric space}, define <X, d>≌<X, d’> iff((?)f) (f is an equilong isomorphism from <X,a> to <x,a’>, for a given <x, d> ∈K, define<x, d> = {<x,d’> ∈K: <X,d’>≌<x,d>}. Let C={<x,d>: <X,d> ∈K},then |C|=|K|=|{d:d is a metric on X}|=2The Theorem 2 illustrates that there exists a nonempty countable set X on which we can define 2nondiscrete metric spaces such that they are not isomorphic each other.