Objective:To study the effect of lithium chloride pretreatment on spatial memory in aged rats’ hippocampuses after exploratory laparotomy. Methods:Twenty-four male SD rats,aged 18 month,were divided into three groups randomly (n=8 each):control group (C),operation group (O) and lithium chloride group (L/O). The rats in group L/O were injected with 2 mmol/kg lithium chloride into their peritoneal once a day and continued seven days,while the rats in the other two groups were injected with same volume of normal saline. All rats were established exploratory laparotomy model on eighth day. After 24 h,the rats’ spatial memory was measured by Morris test. Results:The latency of group C was lower than that of group L/O or group O(P < 0.05);the latency of group L/O was significantly lower than that of group O(P < 0.05);the swimming distance of group C was significantly shorter than that of group L/O or group O(P < 0.05);the swimming distance of group L/O was significantly shorter than that of group O(P < 0.05). Conclusion:Spatial memory was injured after exploratory laparotomy in aged rats. However,lithium chloride pretreatment could obviously improve these changes. It is suggested that lithium chloride pretreatment has potential effects for spatial memory decrease in aged rats after exploratory laparotomy.