Amorphous thin films with a composition of 0.24Pb(Zn1/3Nb2/3)O3·0.384PbZrO3·0.376PbTiO3 (PZNZT) were deposited on PbTiO3 (PT)/Pt(111)/SiO2/Si(100) substrates by room-temperature sputtering. The chemical-oxidation-treated films after deposition were crystallized by varying the pressure in a wide range by hot isostatic pressing (HIP) at a fixed temperature 200°C lower than that adopted in rapid thermal annealing (RTA). All the obtained films were confirmed to be of the single-phase perovskite structure. Particularly, the films HIP-treated at 500°C for 1 h under a mixed gas (Ar/O2 = 80/20) pressure of 1.8 MPa showed almost complete (001) orientation and their degree of c-axis orientation, α, reached up to 0.95. The crystallinity in the films HIP-treated under a high pressure ranging from 8.8 to 176.5 MPa significantly lowered due to an increase in the formation of an amorphous part with increasing pressure. The PZNZT films HIP-treated at 500°C for 1 h under the mixed gas pressure of 1.8 MPa had symmetric and slim hysteresis loop shapes with a remanent polarization 2Pr=23.2 µC/cm2 and a coercive field 2Ec=86.7 kV/cm.