Global climate change has led to a shift in rainfall patterns. And as water is an essential ingredient for plant photosynthesis, shifts in rainfall patterns will inevitably affect plant growth. In this study, the response of leaf traits and photosynthetic fluorescence properties of Fraxinus malacophylla seedlings to rainfall patterns during the dry and rainy seasons was investigated using a natural rainfall duration of 5 d (T) and an extended rainfall duration of 10 d (T+) as rainfall intervals; and a monthly average rainfall as control (W), with the corresponding rainfall treatments of a 40% increase in rainfall (W+) and a 40% decrease in rainfall (W-). The results showed that Pn, Gs, and Tr basically all tended to increase and then decrease with increasing rainfall in the dry season, and generally reached the highest under the W treatment; and Pn, Gs, Ci, and Tr mostly remained high at 5d relative to 10d; PI was overall higher under the W treatment throughout the dry season. Extending the rainfall interval at the beginning of the rainy season significantly reduced Fm; throughout the rainy season, Gs, Ci, and Tr basically showed a decreasing trend with increasing rainfall, reaching the highest under the W-treatment, and mostly higher at 5d than at 10d. These results suggest that natural rainfall intervals and natural rainfall amounts are more favorable to the growth of Fraxinus malacophylla seedlings in the dry season; reduced rainfall and multiple rainfalls in the rainy season tend to promote photosynthesis in Fraxinus malacophylla. This study reflects the different survival strategies of Fraxinus malacophylla under different rainfall patterns, as well as providing a theoretical basis for understanding how Fraxinus malacophylla can grow better under rainfall variability and for future management.