The methanol extract of Callistemon salignus was subjected to different phytochemical tests  and gives positive results for glycosides, tannin, carbohydrate, volatile oil, flavonoid and steroid. This extract leads to the isolation of 3′, 4′, 5, 7-tetra-hydroxy flavonol by chromatographic separation through a graded elution. The identity of the isolated compound was checked by preliminary phytochemical test, TLC study, solubility, melting point determination. Finally the structure was elucidated by different spectroscopic methods such as UV, IR, NMR (13 C NMR and Proton NMR) and LCMS. On the basis of this chemical and spectral evidence and upon comparison with the literature data, the isolated compound is identified .The compound was isolated first time from this plant extract.