Objective:This study aims to modify the transcardial perfusion method to improve the effects of brain fixation in canines. Methods:Seven beagle dogs were randomly divided into three groups:control group(n=1),transcardial perfusion group(n=3),and improved perfusion group(n=3). Canines in the improved perfusion group were anaesthetized and heparin was administrated. The femoral artery access was achieved,then a catheter was inserted into internal carotid artery under fluoroscopic guidance and constituted the inflow,and the right auricle was opened to act as an outflow access. After the ligation of inferior vena cava and abdominal aorta,the brains were perfused with saline followed by paraformaldehyde. Once the perfusion was accomplished,the brains were harvested for HE staining and transmission electron microscopy. Results:Compared with the transcardial perfusion method,the improved perfusion method can significantly reduce the occurrence of cell autolysis,and it is liquid-saving and time-saving. Conclusion:The improved perfusion method is more effective than transcardial perfusion in canine brain tissue fixation,and it is feasible for brain fixation in large animals.