This paper presents a new nanofabrication method for dual drug loaded regenerated silk fibroin (RSF) nanofibers, based on a simple, colloid-electrospinning technique. In this process, curcumin (CUR, hydrophobic drug), loaded in RSF nanospheres, and doxorubicin hydrochloride (DOX·HCl, hydrophilic drug) were blended with aqueous-based RSF solutions to prepare the nanofibers embedded with CUR-loaded nanospheres in core and DOX·HCl in shell. The dual drug loaded nanofibers showed smooth surfaces and relatively uniform diameters and dispersity. The encapsulation of CUR-loaded nanospheres and DOX·HCl were confirmed by electron and fluorescence microscopy. FTIR spectra and X-ray diffraction results indicated that presence of intermolecular hydrogen bonding between drug and RSF fibers and the drugs were presented in an amorphous state in the nanofibers. In vitro dissolution tests showed that CUR-loaded nanospheres/DOX·HCl-loaded RSF core/shell nanofibers exhibited dual drug release profiles and achieved a sustained release, furthermore, the amount of drug release in core or shell phase of nanofibers was tunable by controlling the drug-loaded content and crystal content of nanofibers with water-annealing process at different temperature. The release kinetics study showed that the mechanism of drug release could be described by a Fickian model. This drug delivery system could be potentially used as local multi-drug delivery systems for treatment of several medical conditions, including breast cancer or skin cancer.