An electrospinning process was utilized to obtain iron oxide (Fe3O4)/ polycaprolactone (PCL)/polydimethylsiloxane (PDMS) nanofibers. The morphology of resulting composite nanofibers were tailored by changing PCL and PDMS composition. Furthermore, an external alternating magnetic field (AMF) could lead to morphology change of composite fibers. This result contributed to the structure change and stress relaxation of the composites, resulting from the temperature increase caused by the AMF absorption property of Fe3O4 nanoparticles. The findings in this work could provide new ideas to develop advanced self-folding materials.