The spathes of Phoenix dactylifera L (aerial parts at flowering Stage) are used in traditional medicine and are also exploited commercially as herbal drugs for the treatment of diabetes mellitus. the present study investigates the chemical composition of the spathes. Method of coupling high-performance liquid chromatography (HPLC) with electrospray ionization mass spectrometry (MS) was optimized for the separation and identification of flavonoid. Fragmentation behavior of flavonoid was investigated using The MS, MSn and UV data together with HPLC retention time (Rt) of flavonoids allowed structural. Spectral data for all peaks were recorded in the range of 200- 700 nm. Some flavonoids including three quercetin derivatives (peak8;9;10 of retention time 15.1, 16.2 and 16.8 respectively), one orient in derivative(peak 12 of Rt 17.6 min) and one flavanone derivative (peaks 13 of Rt 18.2 min) were identified in negative and positive modes using full scan mass measurements and MSn fragmentations. All flavonoid derivatives former indicated in flavonic extract of diethyl ether.