We had testified that the decay volatile of fruit could be detected by using infrared spectroscopy. We collected volatile to a gas cell in this methods and used multi-reflecting structure to enhance optical path. In this study, we used open-path infrared spectroscopy to monitor grape decay volatiles and tried both active and passive modes. We qualitatively analyzed the volatiles produced by the decay grape according to the characteristics of infrared spectroscopy, and measured the infrared spectra of the volatiles during storage establishing the method for different decay status according to the changing rules. We also tried to directly analyze the volatile by the origin spectra and demonstrated that it still had obvious spectra characteristics. In this study, It was proved to be feasible using open-path infrared spectroscopy to monitor the decay volatiles. With the advantages of flexible use and non-contact on-line measurement, the method could be applied in large area to monitor the decay status of fruit and even to locate decay source.