Based on the analysis technology of visible/near infrared diffuse reflectance spectroscopy a portable and nondestructive detector was designed to test comprehensive quality of red globe grape bunches in the growth period. The detector included spectrum acquisition probe, spectrometer, lithium battery, halogen lamp light source, advanced RISC machines (ARM) board and peripheral circuit. Based on microsoft foundation classes (MFC) development tool, the real-time analysis and processing software of the detector was written by C++ language. The optimal partial least squares regression (PLSR) detection model of multi-quality parameters was implanted into the hardware device. This paper selected the red globe grapes bunches in the growth period as the research samples, collected the visible/near infrared diffuse refl ectance spectrum information, and then used the established PLSR model to detect the soluble solid content (SSC), total acid (TA) and pH of the samples to generate comprehensive quality parameter. So as to realize the nondestructive detecting of comprehensive quality of red globe grapes bunches in the growth period. In conclusion, the detector could realize real-time and non-destructive detecting of red globe grapes bunches in growth period aiming at the comprehensive quality.