Copper ions play very significant roles as catalytic cofactors in different cellular physiological processes. However, abnormal copper concentrations can also lead to disease and even death. Compared with copper ions, mercuric ions are the most prevalent and hazardous among various heavy metal pollutants owing to their notorious toxicity and bio-accumulation throughout the food chain. Therefore,it is very important to detect them with high sensitivity and selectivity. Fluorescence probe method has become one of the important detection means of Cu²⁺ and Hg²⁺ due to its advantages of high sensitivity, rapid and convenient, visualization and in-situ nondestructive detection. Herein, the design and synthesis of Cu²⁺ and Hg²⁺ ion double recognition fluorescence probes based on small molecules, and their performance and the latest research progress in analysis reported in recent years have been reviewed. The future research and developing trends of such fluorescent probes are prospected.