Low temperature is one of the major environmental stress factors affecting plants, exerting significant influence on photosynthetic capacity and thereby hindering plant growth and development. The impact of low temperature stress on the photosynthetic mechanisms in plant leaves was summarized, focusing on changes in cellular anatomical structure, cell membrane permeability, osmoregulatory substances, and photosynthetic carbon assimilation. In terms of cellular anatomical structure, low temperature stress may disrupt the palisade/spongy tissue ratio in mesophyll cells and damage chloroplast ultrastructure. Regarding cell membrane permeability, low temperature stress induces electrolyte leakage, along with the accumulation of malondialdehyde and reactive oxygen species, leading to membrane lipid peroxidation. Plants counteract this by enhancing the activity of antioxidant enzymes such as superoxide dismutase (SOD) to maintain ROS homeostasis. Concerning osmoregulatory substances, low temperature stress triggers the dynamic accumulation of proline, soluble sugars, and proteins to sustain photosynthetic performance. In photosynthetic carbon assimilation, low temperature stress reduces chlorophyll content and the activity of ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco), altering key photosynthetic parameters such as net photosynthetic rate (Pn) and intercellular CO₂ concentration (Ci). Phosphoenolpyruvate carboxylase (PEPC) compensates for the decline in Rubisco activity by fixing low-concentration CO₂, thereby mitigating photosynthetic losses. In conclusion, this article provides a reference for analyzing the mechanism of plants’ response to low temperatures and improving the photosynthetic performance of plant leaves under low temperature stress conditions.