Let F be a family of meromorphic functions on the unit disc A. Let a be a non-zero finite value and k be a positive integer. If for every f ∈ F,(i) f and f(k) share α ;(ii) the zeros of f(z) are of multiplicity ≥k + 1 , then F is normal on △.We also proved corresponding results on normal functions and a uniqueness theorem of entire functions .