To explore the effect of Wendan Decoction on cognitive disorder in schizophrenic rats through contactin associated protein 3 (CASPR3).Methods:SD rats were randomly divided into a normal group，a model group and an experimental group.In the model group，the rats were intraperitoneally injected with 0.6 mg/kg MK-801 to induce a schizophrenia model.The rats in the experimental group were intragastrically administrated with 20 mL/kg Wendan Decoction，and the rats in the model group and the normal group were intragastrically administrated with 20 mL/kg normal saline.The stereotyped behavior scoring method was used to evaluate the stereotyped behavior scores of the rats 5 and 10 min after modeling.Glutathione peroxidase (GSH-Px)，catalase (CAT)，superoxide dismutase (SOD) kits were used to detect rat serum GSH-Px，CAT and SOD content.The TUNEL method was used to detect the apoptosis of cerebral cortex neurons in rats.Morris water maze was used to test the learning and memory function of rats.Western blotting was used to detect CASPR3 protein expression in rat hippocampus.Results:The stereotyped behavior scores，average escape latency，neuronal apoptosis rate，and CASPR3 protein expression of rats in the model group were higher than those in the normal group at 5 min and 10 min after modeling (P<0.05)，while those of the rats in the experimental group were lower than those in the model group (P<0.05).The levels of serum GSH-Px,CAT and SOD in the model group were lower than those in the normal group (P<0.05)，while those in the experimental group were higher than those in the model group (P<0.05).Conclusion:Wendan Decoction can reduce the cognitive disorder of rats.Its mechanism may be related to the down-regulation of CASPR3 protein expression.