Using the FLS920P spectrometer of Edinburgh Instruments the three-dimensional fluorescence spectra of the fresh orange juice and the three samples of 100% orange juice bought in the supermarket were studied and their characteristic parameters were obtained. The comparison of the spectra and the characteristic parameters shows that they are apparently different, especially at the emission wavelength of 683 nm. This might be caused by the food additives added into the orange juice bought. The three-dimensional spectrum of the fresh orange juice with carrageenan was obtained. The comparison of the samples bought and the one with carrageenan shows that they are with little difference. The characteristic parameters of them are almost of no difference. Thus the conclusion can be drawn that the samples bought all have carrageenan. The results of the paper can somewhat help quantitatively study carrageenan in the orange juice.