To investigate the changes of shock avoidance response in Y maze and the real-time local field potentials (LFPs) on hippocampal CA3 region in adolescent rats with high fat feeding. The juvenile rats of weaning 1 week were fed separately on basic feed (BF) and high fat diet (HFD) for 4 weeks until the puberty. Using the electric shock avoidance training method, the relevant parameters of reaching the learning standard of two groups of rats were recorded, and the LFPs of CA3 region in hippocampus were explored simultaneously by wireless telemetry. Compared with the BF group, the body weight of HFD rats were increased significantly(P<0.05), the rats percentage of reaching the learning standard within 1 to 2 days and the various parameters of shock avoidance recorded in training were all superior to those of BF group rat,the LFP rhythm of bilateral hippocampal CA3 region appeared to the desynchronizd fast wave. The θ and γ1 rhythms of right hippocampal CA3 region shown synchronous increase, but there was no coupling formation in phase-amplitude of the θ and γ1 rhythms. From juvenile to adolescent with HFD intake, the adolescent rat gained an increase significantly in weight,but the ability of shock avoidance and the function of hippocampus-dependent spatial cognition in Y maze had not be expected decline.