Abstract: ¹⁴CO₂ labeling is a method commonly used in the study of transport and distribution of photoassimilate in plant. In order to study the source-flow-sink relationship of photosynthate transport and distribution, ¹⁴CO₂ labeling of single leaf is required. Some of the methods of single-leaf ¹⁴CO₂ labeling reported in the existing literature are complicated and some of the date are too simple, they are not practical. Therefore, through years of practice, we have established a simple and feasible method for preparing and collecting ¹⁴CO₂ and feeding single leaf using the principle of the connector, which provides necessary support for the study of plant photosynthesis.