The electro-spinning conditions, such as, concentration of polymer solution, electric potential, die to collector distance(DCD), electric conductivity of collector, and additives on the change of fiberweb structure and fiber diameter, have been investigated. The results showed that the electric potential and die to collector distance affect the fiber diameter and the fiberweb uniformity. The difference of the electric conductivity of collector and the additives did not affect the fiber diameter, however, the uniformity of the fiberweb was significantly affected. The optimum spinning conditions for the electrospinning of polyacrylonitrile were found as follows; the electrical potential should be in the range of 25 to 30 kV, the DCD 15 cm, and the concentration of polymer solution should be between 12 to $15\%$.