Diabetes is a chronic disease that causes critical health problems, and eventually leads to damage major organs. The number of people with diabetes keeps increasing over the next decade. Diabetes requires lifetime treatment in patients' daily life. Although many patients already know that tight glucose control is a critical factor of success for the quality of life, they still fail to monitor their blood glucose level in actual clinical practice because of the frequent and painful fingerstick tests. The main aim of this research is to design automatic insulin injection system with Continuous Glucose Monitoring (CGM) signals. This system controls the insulin dosage automatically according to the real-time glucose level, so that it can improve the quality of life for those who are suffering from diabetes. The current system we developed can also provide real time glucose data to the end user to manage the diabetes.