Objective: To investigate the correlation between MRI features and pathology in brain edema at the early stage of severe burn (50％ TBSA Ⅲ degree) in dogs.Methods: Fifty-two dogs were randomized into control, simple burn (SB), burn plus sodium lactate (BSL), and burn plus glucose solution groups (BGS). The manifestation of the brain of control group was compared with that of burn groups at 6, 12, 18 and 24 hours postburn with MRI and pathological examination (gross appearance, electron microscopy and light microscopy).Results: The earliest findings of brain edema were seen at 12 hours after burn in BGS group, in which brain swelling was the main feature of MRI. The decrease of SIR on T1WI was not observed until it was exceeded 10％.Signal of T2WI increased by 8.29％ at 24 hours after burn.It was difficult to distinguish the gray matter from the white matter at the boundary line, which became blurred later. Histological changes of brain edema were observed as early as 6 hours after burn, being accompanied by swelling of endothelial cells and peri-vescular astrocytes, and vacuolation took place in neurons at 12 hours after burn, with different degrees of necrosis of capillary endothelimn,neurons, and axons. These changes became more marked with elapse of time. The BGS group showed the most obvious changes mentioned above at 24 hours after burn.Conclusions: The model of the brain edema after severe burn has the feature of both vasogenic edema and cytotoxic edema on the MRI and pathology. Positive MRI findings lagged behind that of the pathomorphological changes. ed