By using RF-5301PC series spectrofluorophotometer,the fluorescence spectrum of Lycium barbarum L.powder is directly acquired to measure the content of vitamin B2(VB2).The collected its fluorescence spectrum is in the band of 530-650 nm.Through MATLAB-based numerical differential and Gaussian fitting algorithms,the fluorescent spectrum information with 563 nm peak under 480 nm excitation has been obtained,and after numerical integral ealculation and linear fitting,it is found that there exists a linear relationship between the integral of fluorescent intensity by wavelength and the content of VB2(R=0.9998 43).The content of VB2 in Lycium barbarum L.powder is measured to be 1.28±0.17 μg/g.The cause of red shift of the fluorescence spectrum of the Lycium barbarum L.powder is illustrated.Our proposed VB2 detection method has many advantages,such as high speed,directness,simplicity,and environment protection,and it is also a powerful tool that could be applied in food security detection.