Continuous blood glucose detection is of great significance in the diagnosis and treatment of diabetes. In this study, an integrated, automated minimally invasive blood glucose continuous detection instrument was designed. Interstitial fluid (ISF) was transdermally extracted by a microfluidic chip, and the volume of the ISF was accurately measured by the single-chip computer. The glucose contained in the fluid was detected by enzyme colorimetry. Then, continuous blood glucose detection was achieved using the correlation of glucose concentration between the interstitial fluid and blood. The glucose concentration in the ISF was obtained by controlling the sample injection, reagent quantification, and absorbance detection in the enzyme colorimetric optical detection module. Owing to the small volume of the ISF extracted through the skin and dispersed on the surface of the skin, in order to facilitate collection, the extracted ISF was diluted with normal saline. To measure the low concentration of the diluted ISF, 10 concentrations in the range of 1—50 mg/dL were selected for absorbance measurement. The absorbance model was established based on the spectral data and glucose concentration. The results show that the glucose detection method has good linearity in the range of 1—50 mg/dL, and the relative standard deviation is less than 0.65%. The instrument is an automation control system and can provide basis for the diagnosis of diabetes. The feasibility of the instrument is verified by test experiments. The instrument has good application prospects for continuous blood glucose monitoring.