A novel coaxial electrospinning process modified from free surface electrospinning has been successfully developed to massive production of core-shell nanofibers in the present paper. A two-layer polymer system, with the lower layer consisting a core polymer solution and the upper layer consisting a sheath polymer solution, is subjected to a sufficient electrical field. As a result, multiple coaxial jets spontaneously form on the edges of the stepped pyramid-shaped spinneret. Compared with the conventional concentric spinneret based coaxial electrospinning, the possibility of clogging was avoided and an enhancement of more than 100 times over the traditionally obtained core-shell nanofibers productivity was obtained. This novel design has potential for high throughput of electrospun core-shell nanofibers. (C) 2014 Elsevier B.V. All rights reserved.