[Abstract] Objective To investigate the effect on learing and memory of mouse who undergone convulsion induced by Ropivacaine toxicity when they were immature. Methods Twenty Sprague-Dawley eighteen days mice were randomly divided into ropivacaine group and Sodium Chloride group (n=10). Morris water maze was performed on mice in both groups for 3days , 2 times per day. The latency period 120s mice were adopted. Mice in R group were intraperitoneally injected with 33.8mg/kg Ropivacaine, and those in N group were administrated with 0.1ml/kg saline. The convulsion mice were adopted to the fifty-five days, since the following days, Morris water maze test was adopted to explore the latency in place navigation, To train study ability in the first three days and test memory ability at the last day. After the test the sections of hippocampus were obtained, and post synaptic density 95 protein(PSD-95) level ,PSD thickness was detected by Weston Blot and electric mirror. Results In Morrios water maze test, there was no singnificant different in latency between R and N group, and there was singnificant different in PSD-95, PSD between R and N group either. Conclusion There was no effect on learing, memory, and PSD-95 in mice who undergone convulsion induced by Ropivacaine toxicity when they were immature. [Key words]: Ropivacaine, convulsion, learning and memory, post synaptic density 95protein