Abstract: Aiming at normal criteria concerning derivative functions and shared meromorphic functions, the result is showed as follows. Let Ω and a(z)(≠0) be a family of functions meromorphic and a meromorphic function in D, respectively. If every μ(z)∈Ω satisfies conditions as follows:(1)μ(z)≠0,(2)for each of the same poles of μ(z) and a(z), the multiplicities in μ(z) are greater than or equal to the multiplicities in a(z),(3)for every functions {μ(z), ν(z)}⊂Ω, μ^(m)(z) and ν^(m)(z) share a(z), then Ω is normal in D. And two examples are given to verify the necessity of conditions(1)and(2).

Key words: the family of meromorphic functions, shared meromorphic functions, normal criteria