The present invention relates to a zirconium based alloy composite having an excellent creep resistance and, more particularly, to a zirconium based alloy composite finally heat -treated to have the degree of recrystallization in the range of 40-70% in order to improve the creep resistance. The zirconium based alloy comprises 0.8∼1.8 wt.% niobium(Nb); 0.38∼0.50 wt.% tin(Sn); one or more elements selected from 0.1∼0.2 wt.% iron(Fe), 0.0 5~0.15 wt.% copper(Cu), and 0.12 wt.% chromium(Cr); 0.10∼0.15 wt.% oxygen(O); 0.006∼0.010 wt.% carbon(C); 0.006~0.010 wt.% s ilicon(Si); 0.0005∼0.0020 wt.% sulfur (S); and the balance zirconium(Zr). The zirconium alloy manufactured with the composition in accordance with the present invention has an excellent creep resistance compared to a conventional Zircaloy -4, and may effectively be used as a nuclear cladding tube, supporting lattice and inner structures of reactor core in the nuclear power plant utilizing light or heavy water reactor.