Abstarct: Phenolic compounds are secondary mextabolites that are produced during the natural growth of most plants and also in response to environmental stress conditions in the plant. These compounds are of interest to industries such as chemical, pharmaceutical and food due to their important functional properties and are vulnerable to oxidizing factors such as light, moisture, etc. The purpose of this research is to encapsulating the phenolic compounds of rhubarb stem's juice with chitosan and soy protein isolate and their effect on the properties of pomegranate juice. For this purpose, the phenolic compounds of rhubarb stem's juice were extracted by methanol and coated with chitosan and soy protein isolate by nanoemulsion method, and finally the resulting microcapsules were used to enrich pomegranate juice samples. The results of Folin–Ciocalteu test showed the highest percentage of microencapsulation efficiency of phenolic compounds with soy protein isolate (45.26%). The results of SEM images showed that the particles were relatively spherical and with a relatively smooth surface, also chitosan nanocapsules with an average size of 281.4 nm and soy protein isolate microcapsules with an average size of 22.33 µm were formed. According to the sensory evaluation results, the samples containing 5 mg of chitosan nanocapsules and 34 mg of soy protein isolate microcapsules were selected for further analysis. The results of pH analysis showed that the samples enriched with chitosan nanocapsules and soy protein isolate microcapsules showed more and less pH decrease than the control samples during the storage period, respectively Colorimetric results showed that the L* index increased only at the end of the first month of storage under the influence of enrichment compared to the control samples, and in the rest of the months, it did not show a significant difference (P<0.05) with the control sample. The results of the viscosity test showed that the enrichment of pomegranate juice with chitosan nanocapsules and soy protein isolate microcapsules has no effect on viscosity, And finally, the investigation of DPPH radical inhibition showed that the enrichment of pomegranate juice with chitosan nanocapsules increased the antioxidant activity of the samples for up to 3 months of storage.