Objective To observe the effects of saponins of Panax notoginseng (PNS) on the brain energy metabolism and mitochondrial respiratory function of oxidative damaged rat model mimic to Alzheimer disease (AD). Methods Oxidative damaged rat model mimic AD (AD group) was established by injection of dihydroxy fumaric acid (DHF) and FeCl3 ADP into the left lateral ventricle of rats. The contents of adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), and phosphate creatine (Pcr) in brain were determined by high performance liquid chromatography (HPLC). The mitochondrial functions (R3, R4, P/O, and OPR) were observed by Clark oxygen electrode method. The difference in the above parameters in rats in the control group (injection of saline), model group, and administration group (injection of PNS) was observed. Results The levels of ATP, Pcr, and R3, R4, P/O, and OPR of rats in AD group were significantly lower than those in the control group (0.9% NaCl instead of DHF FeCl3 ADP), but those in PNS group were higher than those in the AD group. Conclusion PNS can improve brain energy metabolism and mitochondrial function of oxidative damaged rats, suggesting that PNS could be used for the treatment of AD.