The aim of this study to purified the cinnamic acid from the cinnamon bark. The partial purified cinnamic acid is obtained after column chromatography application. Thin layer chromatography (TLC) elution yielded pure crystals, which identified as cinnamic acid in comparison with the standard cinnamic acid 10.5 mg / 150 gm cinnamon bark powder obtain as a result of partial purification by TLC. Chemical tests for identification compound of extract crystals yield were included: general tests for phenolic compound, HPLC (High performance Liquid Chromatography) analysis and melting point estimation, in relation to standard cinnamic acid for tests. Concentration of cinnamic acid was 96%.