The invention provides a method for predicting the diameter of electrospun nanofibers based on the height of a Taylor cone. The method is characterized by comprising the steps of applying different voltages to conduct electrospinning, measuring the height of the Taylor cone formed through polymer fluid in the electrospinning process, measuring the diameter of the obtained nanofibers through a scanning electron microscope, establishing a linear relationship between the height of the Taylor cone and the diameter of the nanofibers, and based on the linear relationship, predicting the diameter ofthe nanofibers by measuring the height of the Taylor cone. By means of the method, powerful monitoring and detection tools can be provided for industrial production and commercial application of the electrospun nanofibers.