Abstract:Total soluble solid（TSS），titratable acidity（TA）and vitamin C（VC）are important characteristic index for evaluating the internal quality and flavor of citrus.In this experiment，near infrared spectroscopy（NIRS）was used to detect the internal quality of tarocco blood orange nondestructively and rapidly.Near infrared spectroscopy （NIRS）was used to collect 300 original spectral data of 100 tarocco blood orange samples，and 100 average spectra were obtained 67 of them were used as correction sets and 33 as prediction sets.Partial least squares （PLS） was used to establish correction and prediction models，and then the performance of the PLS model was evaluated through actual verification.The correlation coefficients r of predicted and actual values of TSS，titratable acid and VCwere 0.833，0.699 and 0.925.The PLS model was validated in practice.The difference of TSS was less than 1%，accounting for 71.43% and VCwas less than 5 mg/100 mL，accounting for 70.00%.The results showed that NIRS could be used as a fast and nondestructive method to detect the intrinsic quality of tarocco blood orange，but the correlation coefficient of titratable acid was poor，which needed further study.