In this study, the surface functionalization of polyacrylonitrile (PAN) fibers was achieved by depositing ZnO nanoparticles using thermal solvent coating, surface morphology, crystalline structure, surface chemistry, thermal stability and washing stability of the ZnO coated PAN fibers were investigated by scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform Infra red spectroscopy (FT-IR), Thermo-gravimetric analyses (TGA) and washing stability test, respectively. In addition, the weight changes after coating and washing were studied at different coating and washing conditions. The SEM images revealed that the ZnO was well coated on the surface of the PAN fibers and the coating was obviously affected by the experimental temperature. The FT-IR spectra indicated the chemical features of the deposited ZnO nanostructures. The XRD patterns showed that there was a typical crystalline structure of ZnO nanogains formed on the PAN fibers after coating. The TGA results revealed that the thermal stability of the PAN fibers was improved by the ZnO coating. The experimental results of washing stability revealed the effect of temperature on the washing stability. Weight measurements indicated that the amount of ZnO deposited on PAN fibers increased with the increasing of coating temperature from 60 to $70^{circ}C$. Weight measurements also revealed that the weight of the ZnO coating on fibers decreased with the increase in washing temperature and washing time.