A fruit and vegetable infrared drying online realtime detecting system was designed. Using the quality sensor, the AD temperature sensor, the PCI8310 data acquisition card and so on, the data of fruits and vegetables in the drying equipment were stored in PC. These data were processed and visualized by the program written by the Visual Basic, and then, drying curves, radiation temperature variation curves and material temperature variation curves were generated. The detecting experiment results showed that the online detection error was within ±003% and the characteristics were displayed accurately and timely. 