In this paper，the detection of the high blood glucose（BG） volunteers characteristics VOCs in breath gas was performed with a homemade PTR-MS.An improved real time online breath analysis system was used for the analysis of 70 normal volunteers and 22 volunteers who suffered from BG.The date were statistically analyzed by Mann-Whitney U test and linear discriminant stepwise regression.The five product ions of VOCs which showed significant differences between the two groups were identified.The mass to charge ratio（m/z） of the five VOCs were m/z 61,31,120,104 and 82，respectively.The five VOCs diagnostic values were evaluated by Receiver operating characteristic（ROC） curve.The area under ROC（AUC） was 0.926，and the specificity and sensitivity were 84.3% and 86.4%，respectively.This paper also focused on the investigation of the acetone concentration distribution in the two groups of volunteers breath gas，and the statistical analysis results showed that the acetone in two groups had no significant difference，and the acetone concentration and blood sugar concentration had also no significant correlation.