Abstract: To investigate the effects of low-temperature stress on winter wheat at the booting stage, this study employed chlorophyll fluorescence imaging (CFI) technology to explore the impact of different low-temperature treatments on the photosynthetic performance of winter wheat. Low-temperature treatments were applied to potted winter wheat using a PGC-FLEX artificial climate chamber. Three low-temperature treatments were established: T1: 12 ℃/4 ℃ (day/night), T2: 8 ℃/0 ℃(day/night), and T3: 4 ℃/-4 ℃ (day/night). Potted plants maintained in the field served as the control group (CK). Apart from temperature, environmental factors such as photosynthetically active radiation (PAR) and relative humidity were set according to the climatic characteristics of the experimental site during the same period over the past five years. During the experiment, environmental factors other than temperature inside the climate chamber were consistent with the outdoors. This experiment measured parameters including chlorophyll fluorescence intensity (CHL), actual quantum efficiency of PSII (Φ_PSII), photochemical quenching coefficient (qP), non-p.5hotochemical quenching coefficient (NPQ), quantum yield of non-regulated energy dissipation in PSII (ΦNo), quantum yield of regulated energy dissipation in PSII (ΦNPQ), and reflection intensities of blue (475 nm) and red (640 nm) light (BLUE, RED). The probability density distribution of each parameter was calculated using the weighted Gaussian kernel density estimation formula, and the skewness and kurtosis of each probability density distribution curve were also calculated, to analyze the effects of low-temperature stress on the photosynthetic physiology of winter wheat at the booting stage. The results indicated that low-temperature stress significantly affected chlorophyll content and photosynthetic efficiency in winter wheat. As the stress temperature decreased, CHL, Φ_PSII, and qP values significantly decreased, their probability density distributions shifted towards lower values, and the overall distribution dispersion increased; BLUE, RED, NPQ, ΦNo, and ΦNPQ values significantly increased, their probability density distributions shifted towards higher values, and the overall distribution dispersion increased. Compared to CK, CHL in T1, T2, and T3 significantly decreased by 2.5%, 15.1%, and 17.0% (P < 0.01), respectively; BLUE increased by 8.5%, 10.6%, and 12.0%; RED increased by 6.8%, -4.4%, and 12.7%; Φ_PSII decreased by 5.6%, 12.4%, and 20.7% (P < 0.01); qP decreased by 4.5%, 4.3%, and 8.6% (P < 0.01); NPQ increased by 4.5%, 3.7%, and 22.0% (P < 0.01); ΦNo increased by 9.0%, 11.0%, and 22.4% (P < 0.01); ΦNPQ increased by 1.0%, 2.7%, and 18.6% (P < 0.01). Low-temperature stress led to decreased chlorophyll content, structural damage to PSII reaction centers, and obstruction of the electron transport chain. At the T1 stress level, light energy allocation was still dominated by photochemical reactions, with minor stress impact. At the T2 and T3 stress levels, the proportion of thermal dissipation gradually increased, dominated by non-regulated energy dissipation, indicating greater stress impact. Under the T3 stress temperature, the photosynthetic system was impaired, and photosynthetic energy allocation became unbalanced, potentially affecting subsequent dry matter accumulation and yield formation. The coefficient of variation analysis for each parameter showed that ΦNo, Φ_PSII, NPQ, and CHL were more sensitive to low-temperature changes and could serve as indicators for evaluating the severity of low-temperature stress in winter wheat at the booting stage.