Abstract: A review on the preparation of carbon dots,carbon source materials as well as application of carbon dots in fluorescence analysis(including biological imaging, biological molecule detection and metal ion detection)was presented. Methods for preparation of carbon dots comprising the methods of top-down (including arc discharge method, laser ablation method, electrochemical method and acid oxidation method) and bottom-up (microwave method, hydrothermal method and ultrasonic method) were described. Prospects on the trends of development in this field were also given (79 ref. cited).