In this paper, we explore the dynamic changes in photosynthesis and chlorophyll fluorescence in Kandelia candel leaves from restored mangroves in southern Zhejiang Province to provide a scientific basis for the ecological restoration and northward migration of Kandelia candel. Using a LI-6800F portable, automatic photosynthesis-fluorescence measurement system, the diurnal variation of photosynthesis and chlorophyll fluorescence of Kandelia candel were measured for one day each month in 2019; the data was then used to analyze the relationship between the two parameters. The results showed that, except for water use efficiency (W_UE) and non-photochemical quenching (N_PQ), the diurnal variation curves of the parameters were generally u-shaped or inverted u-shaped; examples of these parameters included transpiration rate (E), stomatal conductance (G_sw), electron transfer rate (E_TR), and maximum photochemical reaction quantum efficiency ( $F_{\rm {v}}' $ / $F_{\rm {m}}'$ ). Some parameters, such as net photosynthetic rate (A), E, G_sw, and E_TR, were found to be significantly higher in July and August than in November and December. In addition, except for W_UE, the correlation between photosynthetic factors and fluorescence factors was significant on a daily basis, and the correlation between A, E, G_sw, W_UE, and E_TR was significant on a monthly basis. The results also demonstrated that the photosynthetic capacity of Kandelia candel leaves was the strongest around noon on any given day; at the monthly level, the strongest capacity was observed in the summer, followed by spring and autumn, and lastly winter. The correlation between photosynthesis and chlorophyll fluorescence of Kandelia candel leaves on individual days was higher than that at the monthly level.