Abstract: This study aims to investigate the effects of low-temperature stress on winter wheat at the booting stage. Chlorophyll fluorescence imaging (CFI) technology was employed to explore the impact of the different low-temperature treatments on the photosynthetic performance of the winter wheat. Low-temperature treatments were applied to the potted winter wheat using a PGC-FLEX artificial climate chamber. Three treatments were established: T1: 12℃/4℃ (day/night), T2: 8℃/0℃(day/night), and T3: 4℃/-4℃ (day/night). Potted plants in the field served as the control group (CK). The environmental factors (such as the temperature, photosynthetically active radiation (PAR), and relative humidity) were set according to the climatic features of the experimental site during the same period over the past five years. The temperature was varied inside the climate chamber. Some parameters were then measured, including the chlorophyll fluorescence intensity (CHL), actual quantum efficiency of PSII (ΦPSII), photochemical quenching coefficient (qP), non-photochemical 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. The skewness and kurtosis of each probability density distribution curve were also calculated in order to analyze the effects of the low-temperature stress on the photosynthetic physiology of the winter wheat at the booting stage. The results indicated that the low-temperature stress significantly dominated the chlorophyll content and photosynthetic efficiency in winter wheat. The values of the CHL, ΦPSII, and qP significantly decreased as the stress temperature decreased. Their probability density distributions were shifted towards the lower values. There was an increase in the overall distribution dispersion; The values of the BLUE, RED, NPQ, ΦNo, and ΦNPQ significantly increased, where their probability density distributions were shifted towards the higher values. There was an increase in the overall distribution dispersion. Compared with the CK, the CHL values in the T1, T2, and T3 significantly decreased by 2.5%, 15.1%, and 17.0% (P<0.01), respectively; The BLUE increased by 8.5%, 10.6%, and 12.0%; The RED increased by 6.8%, -4.4%, and 12.7%; The ΦPSII decreased by 5.6%, 12.4%, and 20.7% (P<0.01); The qP decreased by 4.5%, 4.3%, and 8.6% (P<0.01); The NPQ increased by 4.5%, 3.7%, and 22.0% (P<0.01); The ΦNo increased by 9.0%, 11.0%, and 22.4% (P<0.01); The ΦNPQ increased by 1.0%, 2.7%, and 18.6% (P<0.01), respectively. Low-temperature stress also decreased the chlorophyll content, structural damage to PSII reaction centers, and obstruction of the electron transport chain. At the T1 stress level, the light energy allocation was still dominated by the photochemical reactions, particularly with the minor stress impact. At the T2 and T3 stress levels, the proportion of thermal dissipation gradually increased, which was dominated by the non-regulated energy dissipation, indicating the greater stress impact. The photosynthetic system was impaired under the T3 stress temperature. The photosynthetic energy allocation was unbalanced to potentially affect the subsequent dry matter accumulation and yield formation. The coefficient of variation analysis for each parameter showed that the ΦNo, ΦPSII, NPQ, and CHL were more sensitive to the low temperature. These indicators can be expected to evaluate the severity of the low-temperature stress in winter wheat at the booting stage.