Fibrinogen plays a necessary role in blood clotting and wound healing. In this study, a new solvent mixture of formic acid/acetic acid with low toxicity was investigated as an alternative solvent for fibrinogen electrospinning. The nanofibers were analyzed by scanning electron microscope (SEM), simultaneous thermal analysis (STA) and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The results showed that when the ratio of formic acid to acetic acid was 75/25 (v/v) the finest defect-free fibres with diameters ranging from 184 +/- 37 to 241 +/- 70 nm were obtained. In addition, the average fibre diameters increase with increasing concentration of fibrinogen from 10wt% to 12wt%. It is concluded that solvent mixture consisting of formic acid/acetic acid can be a great solvent for electrospinning of fibrinogen and is able to produce nanofiber structures.