Rubber composite fibers con fling silver nanoparticles with high morphological stability were prepared through combination of electrospinning and in-situ chemical crosslinking. The composite fibers included those of Ag/polybutadiene rubber (BR), Ag/polyisobutylene-isoprene rubber (IIR), and Ag/silicon rubber (SiR). During the study, Ag nanoparticles (Ag NPs) were first generated through reducing the Ag ions in rubber/N,N-dimethyformamide/tetrahydrofuran solutions upon ultraviolet-irradiation; subsequently, rubber composite fibers with uniform diameters from hundreds of nanometers to several micrometers were made by electrospinning the above solutions. The electrospinning was carried out with in-situ chemical crosslinking. The results indicated that chemical crosslinking during (and shortly after) electrospinning was able to improve substantially the morphological stability of rubber fibers. As indicated by the results acquired from UV absorption spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscope, Ag nanoparticles with sizes of 10 similar to 20 nrn were uniformly dispersed in rubber fibers. It was believed that, in addition to the protection of polyvinyl pyrrolidone, a rapid solvent evaporation and limited motion space for a very fine fiber during electrospinning could prevent/mitigate the aggregation of Ag NPs, resulting in a very uniform dispersion. The electrospun Ag NPs/BR composite fibers made of the solution containing very low loading amount (3 wt%) of AgNO3 demonstrated strong antimicrobial activity.