Through the addition of nano-silicon dioxide in the pure polyphenylene sulfide, the masterbatches were obtained, then using melt spinning technology to prepare SiO₂/PPS fiber. The structure and heat-resistant properties of samples were characterized by transmission election microscopy (TEM), infrared spectrum (IR), differential scanning calorimeter (DSC) and other measurements. The experiment results indicate that the mechanical and heat resistance properties of PPS fiber were improved after adding the content of 1%wt nano-silicon dioxide. When the fiber was heated at 230°C for 24 hours, the breaking strength and elongation increased by 2.412cN/dtex and 11.90% compared to the pure PPS fiber. Moreover, the working temperature raised by 50°C.