A method of 1H qNMR was developed for the determination of sildenafil citrate，tadalafil and vardenafil added in dietary supplements illegally.In this experiment，Bruker Avance DRX 500 was applied，with deuterated dimethylsulfoxide（DMSO-d6） as solvent and 2,3,5-triiodobenzoic acid as internal standard substance.The spectral width，center frequency，pulse width，relaxation delay and the number of scans were optimized，and the method was validated.The results showed that,the correlation coefficients for the linear regression were not less than 0.999.The detection limits of the method for sildenafil citrate，tadalafil and vardenafil were 0.045，0.026，0.033 mg/mL，and the quantitation limits were 0.218，0.128，0.159 mg/mL，respectively.The inter-day RSDs were 0.38%，0.85%，0.34%，and the intra-day RSDs were 0.72%，1.2%，1.4%，respectively.The accuracy of the method was also verified by comparing the results of 1H qNMR and HPLC-DAD，testing the same 13 samples.The results showed that the RSDs of two methods were between 1% and 8%.