A NMR method was developed for the determination of vitamin B2(VB2) in vitamin B2 tablets.NMR determination conditions were as follows:the pulse sequence:cpmgpr1d,hydrogen spectral width:6 009 Hz,pulse width:11.95 μs,delay time:6.50 μs,temperature:27 ℃,number of scans:32.A good linear relationship was obtained between peak area ratio of VB2 to TSP and concentrations of VB2 in the range of 1.25-10 mg/mL.The regression equation was y=2.989 4 x+0.185 5(r2=0.999 2).The average recovery was 83.2 %.The results indicated that the NMR based method had high sensitivity and good repeatability,and could be used in the determination of VB2 in vitamin B2 tablets.