Abstract: In this experiment, blueberry was used as experimental material. Dynamic monitoring of the chemical group in blueberry fruit extract was implemented by GC-MS pre-column derivatization method and the effect of pH ( 3.0 ~ 9.0) on the chemical composition of blueberry were investigated.The experimental results were as follows: 39 compounds in blueberry fruit extraction were identified, including sugars, acids, alcohols, esters and ketones five categories.The total content of sugars, acids and esters showed a decreasing trend with pH from acid to alkaline, but the total content of alcohols and inosose showed a increasing trend.Moreover, we found a new material namely arabinopyranose which was gradually decreasing with the increase of pH in pH7.0~9.0.By dynamic monitoring the high content of saccharides and acid compounds of blueberry extract, we found that saccharides with the pH from acidic to alkaline, while glucose and arabinopyranose showed a increasing trend with the pH increase.The experimental results provide a theoretical basis for the deep processing technology of blueberry resources affected by pH.