Development of methods for the functionalization of fibrous materials to improve properties meets the increasing demand for technological needs in various fields. The use of a combination of two immiscible polymers in a filament can allows new high added-value advanced structures. In this study, melt spinning technology was adopted for the polypropylene/polyvinyl alcohol (PP/PVA) blends containing silica nanoparticles, aimed at fabricating biphasic fibers with unevenly distributed silica nanoparticles. The localization of silica nanoparticles has been revealed mainly due to the thermodynamic factors, and the design can help produce a surface-decorated fibrous scaffold with embedded nanoparticles after the selective extraction. The fiber morphology was also investigated by Scanning Electron Microscopy (SEM). Its mean diameter of PVA dispersed phase within PP matrix can reach submicron scale, with the specific interface area over 3.2 m2/g, which can provide a fiber porous structure. In addition, the mechanical properties of the multifilament fibers were studied via tensile test as well, and the interface-located silica nanoparticles has the slightest impact. Its mechanical properties can be maintained to a great extent as well, which gives a premise for further textile utilization.