In this research, we have investigated the effect of several parameters such as solution concentration, solvents mixture, voltage, viscosity, solution conductivity, surface tension, solubility parameter and spinning distance on the morphology of polycarbonate nanofiber. The main purpose of this research was to improve fiber morphology by choosing the best solvent. In order to determine the range of concentration of polymer, some electrospun mats with concentrations of about 10 to 15 weight percent (polycarbonate in methylene chloride (MC)), applied voltage 25 kV, tip to target distances 12cm and the mass flow rate of 1 ml/h were prepared. Evaluation of voltage determined that increase in voltage will change fiber morphology and bead density and 20 kV voltage is suitable for electorspining of polycarbonate solution.When the viscosity and surface tension increased, the fiber elongation became harder. Wherease increase in dielectric and conductivity caused decrease in fibers diameter. Studying the effect of different solvents showed that the MC is the most suitable solvent. The effect of different solvent mixtures of MC and DMF were investigated to determine appropriate ratio of solvents. The morphology of electrospun fibers was studied using scanning electron microscope (SEM). The results showed that the distance of 12cm was appropriate and therefore this distance was chosen as spinning distance. In this research, the effect of solubility parameter on fiber morphology and viscosity were also investigated. The results showed that the viscosity increases with increasing the difference between the solubility parameters of the solvents mixture and polymer, as a result of the electrospun fibers did not have appropriate morphology.The study of the surface tension of solutions showed that increasing surface tension led to bead formation along the fibers. Investigations of conductivity showed that this parameter decreases the negative effect of viscosity and surface tension increase on fiber morphology.Finally, mechanical properties of electrospun polycarbonate nanofiber mats in different mixture of solvents were investigated. The results of these investigations showed that highest strength and modulus belonged to the solvent mixture of 90:10 and 80:20