The NdBaCuO superconductor samples were zone-melted in low oxygen partial pressure (1%O+99%Ar). The zone-melting temperature was decreased about 12 film 1,06, the zone-melting temperature in air. Thus the loss of liquid phase (BaCuO and CuO) was reduced during: the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased and, therefore, the substitution of Nd for Ba was occurred. The superconductivity of zone-melted NdBaCuO prepared under low oxygen partial pressure was distinctively improved.d.d.d.