Brain cooling is an effective method for suppressing abnormal brain activity and reducing brain inflammation, particularly in conditions such as epileptic seizures and cerebral infarction. Traditional focal brain cooling techniques, that use devices like Peltier elements are effective, but can cover only a limited area. To overcome this limitation, we introduced a thin, flexible thermally conductive sheet that can extend the cooling range without an increase in the size of the cooling source. This study employed a severe cerebral infarction model in cats to evaluate the efficacy of this approach, and aimed to prevent ischemic damage and explore potential therapeutic applications. The middle cerebral artery (MCA) was occluded for 3 h, followed by reperfusion. Cooling was then initiated using the thermally conductive sheet, which was placed over the perfusion area with the cooling source positioned on the ectosylvian gyrus. Cooling was continued for 24 h, during which ECoG (electrocorticographic activity) and brain temperature were simultaneously monitored to assess both immediate and long-term effects. Results demonstrated that the thermally conductive sheet effectively reduced brain temperatures of a broad area below 20 ℃. This significantly limited the expansion of the infarct size compared to focal cooling. However, significant cerebral edema persisted despite these benefits, indicating that broad cooling alone may not be sufficient to mitigate brain swelling. These findings indicate that though extensive cooling can effectively reduce infarct size, additional strategies, such as anti-inflammatory therapies, are needed to optimize outcomes in patients with severe cerebral infarction.