With Fe(acac)3 as Fe3+source and H2PtCl6·6H2O as Pt4+source, FePt nanoparticles were prepared via chemical reduction process using NaBH4 and poly (N-vinyl-2-pyrrolidone) (PVP) as reductant and surfactant, respectively. The effect of PVP on magnetic properties of FePt nanoparticles was investigated. The as-prepared FePt nanoparticles were characterized by X-ray powder diffraction (XRD), transmission electronmicroscopy (TEM) and vibrating sample magnetometer (VSM). The results show that PVP modified FePt nanoparticles are of face-centered-cubic (fcc) structure, which are spherical shapes with good mono-dispersibility. The particles display superparamagnetic as the coercivity is zero. For the FePt nanoparticles with PVP/Fe(acac)3=7:1, the structure transforms from face-centered-cubic (fcc) to face-centered-tetragonal (fct) after the sample is annealed at 600 °C for 30 min in argon atmosphere, with its coercivity reaching as high as 5400 A·m-1