Qualitative and quantitative determinations on main components in health food were performed by the nuclear magnetic resonance(NMR) techniques such as diffusion-ordered NMR spectroscopy(2D-DOSY) and pulse length based concentration determination(PULCON).In this experiment，Bruker Avance Ⅲ 600 MHz was applied,with acetone-d6 as solvent.2D-DOSY spectra demonstrated that the sample contained three compounds.1H-1H correlation spectroscopy(COSY) and total correlation(TOCSY),1H-13C heteronuclear single quantum coherence spectroscopy(HSQC) and 1H-13C heteronuclear multiple bond correlation(HMBC) were used to assign the chemical shifts of the compounds,which were finally determined to be diethyl phthalate,melatonin and omeprazole.Finally,a quantitative PULCON method was developed to determine the contents of by-products,and the contents of the three compounds were 16.65,5.38,46.35 mg/g,respectively.The results indicated that the NMR spectroscopy,compared with HPLC method,is a more direct and rapid method for analysis on the structures and contents of non-target compounds in health food with no need of standard reference and separation.