To establish a mathematical model of visible and near infrared diffuse reflection(VIS/NIR) spectroscopy and firmness of sweet persimmon,and to evaluate the applicability of VIS/NIR spectroscopy in non-destructive measurement of firmness of sweet persimmon.peel brittle,peel strength and the average hardness of flesh of the fruit were used as evaluation indexes.In the spectral region between 400～2500nm,calibration results for firmness of sweet persimmon were compared with different derivative treatments and different scatter and standard treatments with modified partial least squares(MPLS).The results showed that the MPLS model,with respect to the first derivative D1 Log(1/R)and standard multiple scatter correction,provided better prediction for peel brittle and peel strength,the correlation coefficient of prediction(R2P)was 0.858,0.858 respectively;the root mean square error of prediction(SEP)was 0.157,0.094 respectively;ratio performance deviation(RPD)was 2.63,2.47 respectively.The MPLS model,with respect to the first derivative D1 Log(1/R)and standard multiple scatter correction,provided better prediction performance for average hardness of the flesh,with R2P 0.82,SEP 0.063,and RPD 2.35.Therefore,this visible and near-infrared diffuse reflectance spectroscopy technique can be used for non-destructive testing of fruit firmness in sweet persimmon.