In this paper, ultrahigh molecular weight polyethylene (UHMWPE) superfine fiber was fabricated by flash-spinning method using UHMWPE as the fiber-forming polymer, 1, 2-dichloroethane as the main solvent. Use central composite design principle, the four factors which mainly influenced the properties of the fiber: spinning temperature, spinning pressure, spinning solution concentration，room temperature were designed for the experiments on the basis of single factor experiment. It can be seen from the results that the predict value are very close to the actual value, the sequence that the factor impact on the overall property of the fiber is: spinning solution concentration>spinning temperature>spinning pressure>room temperature. The optimum condition obtained is: spinning temperature is 196.6 °C, spinning pressure is 12.7MPa, spinning solution concentration is 6.3%, at room temperature 15.1 °C, and the overall property of the fiber was 92.9 under these conditions. Spinning fiber under the optimum condition use 5L autoclave, and the overall performance of the fiber had an average of 91.2. So it is feasible that using this method to optimized the flash spinning process.