Poly（m-phenyleneisophthalamide）(PMIA) has been widely applied in special protective clothing, high temperature filter materials, electrical insulating materials and honeycomb structure wainscoting materials, etc. for its excellent properties. Most of the studies focused on micron fibers at present, however, there were little researches on PMIA nanofibers obtained by electrospinning. PMIA solution was prepared by putting it into the LiCl/DMAc solvent systems and subsequently heating it. Consequently the effect of temperatures on the solubility, the viscosity and conductivity were analysed. PMIA nanofiber mats were obtained by electrospinning. Morphologies and diameter distributions in different electrospinning processes were studied. The processing parameters included spinning solution concentration, voltage, collecting spinning distance (C-SD). Finally the optimized parameters were achieved as follows: dissolve temperature 90°C, spinning solution concentration 12wt%, high voltage 23 kv, C-SD 11 cm.