In this study by exerting a simple modification over the spinneret of rotating-jet electrospinning method, the alignment degree of electrospun fiber was improved. For this propose a layer of plastic insulation was covered onto the spinneret of the rotating-jet electrospinning method. SO, the effective length of spinneret which controls the strength of electrostatic field was changed. To evaluate the effectiveness of this modification, the obtained results for various spinneret effective lengths at various voltages were compared with published data. It was revealed that, as the effective length of spinneret is decreased from 3.2 cm to 0.5 cm the alignment degree is increased more than three times.