A solution-phase approach to the synthesis of nano-Se/silk fibroin colloids(NSeSFC) by reducing selenious acid solution with silk fibroin(SF) was proposed, and the composites were in situ prepared by macrowave method. The nanocomposites were characterized with ultraviolet-visible(UV-Vis) absorption spectrometry, resonance Rayleigh scattering(RRS) spectrometry and transmission electron microscopy(TEM). The nano-Se(O) solution exhibited the strongest resonance Rayleigh scattering at 579 run. Through the RRS discussion, we found the best preparation and conservation condition of NSeSFC. The TEM image shows the sizes of the Se(O) particles were about 50 nm and dispersed equably. The resulted NSeSFC exhibited good stability, and it can be kept for a long period.