Zirconia nanopowders were prepared via polyzcrylamide gel route with different zirconium salt, including ZrOCl2·8H2O, Zr(SO4)2·4H2O and ZrO(NO3)2·2H2O. Thermogravimetric analysis (TG), differential scanning calorimetry analysis (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the thermal decomposition process of xerogel, phase compositions and morphologies of zirconia nanopowders. The influence of different zirconium salts on the phase transformation, phase compositions and morphologies of the as-prepared zirconia nanopowders by polyacrylamide gel route were studied. The results demonstrate that zirconium salt affects thermo-decomposing temperature of polyacrylamide gel. When precursor is zirconium oxynitrate, the thermo-decomposing temperature of xerogel is the lowest which is around 530 ℃. When precursors are zirconium sulfate and zirconium oxychloride, the thermo-decomposing temperatures of xerogels are around 573 ℃ and 580 ℃, respectively. Zirconium salt affects the crystallization temperature of zirconia, but the phase transformation of zirconia is similar, which transforms from amorphous to tetragonal and completely converts to monoclinic at 900 ℃. The higher the crystallization temperature of zirconia, the smaller the mean particle size, the more particle agglomeration. The nearly spherical zirconia nanopowders can be prepared and the particle size distribution is within the range of 52~97.4 nm with the above three zirconium salts as precursors.