High concentration of rutin nanosuspension (5%) in water was prepared by using high-speed and high-pressure homogenizer. Sodium tripolyphosphate (STPP) crosslinker and chitosan polymer were found to be an efficient encapsulating reagent and stabilizer to prepare rutin nanosuspension. In addition, the particle sizes and sedimentation rates of rutin nanosuspension were investigated under effects of several factors, including applied pressures of homogenization, the presence of co-solvent PEG 400 (polyethylene glycol 400), chitosan loading, STPP and chitosan mass ratio. Raw rutin material was characterized using powder X-ray diffraction (XRD) and high-performance liquid chromatography (HPLC). To evaluate the parameter of rutin nanosuspension, laser diffraction spectrometry (LDS) was employed to estimate the particle size distribution. Rutin nanosuspension prepared under optimal conditions was freezing dried/spray dried to form rutin powders. Properties of the rutin powders were evaluated using XRD analysis and re-dispersion into aqueous solutions of different pH values.