The effects of Hyungbangjiwhangrang on the enhancement of learning and memory of AD model rats were studied with Morris water maze and radial arm maze. Sample group was electrolytically lesioned on nbM, and then daily treated with the medicine for two months. Control group with nbM lesion, and sham group with the sham operation were treated the vehicle for same duration. The following results were observed.1. As the learning trials of Morris water maze processed repeatedly, sham group achiened 201.64${\pm}$33.13 seconds in 1st trial, 153.14${\pm}$61.80 seconds in 2nd, 106.21${\pm}$46.81 seconds in 3rd, 76.64${\pm}$48.40 seconds in 4th, and 52.29${\pm}$38.25 seconds in 5th. The control group achieved 224.08${\pm}$29.16 in 1st trial, 191.77${\pm}$67.97 seconds in 2nd, 177.77${\pm}$65.44 seconds in 3rd, 140.92${\pm}$68.27 seconds in 4th, and 126.46${\pm}$79.15 seconds in 5th. The sample group achieved 223.36${\pm}$23.33 seconds in 1st trial, 215.86${\pm}$38.93 seconds in 2nd, 190.79${\pm}$51.57 seconds in 3rd, 155.79${\pm}$62.67 seconds in 4th, and 127.93${\pm}$62.11 seconds in 5th. Therefore, these data shows that all three groups were improved in learning capacity as trials were repeated, but the shame group showed prominent improvement in learning compared with the control group(p<0.05).2. In memory retention test of Morris water maze that counts the staying time in the target area, sham group stayed for 15.36${\pm}$5.39 seconds, the control group stayed for 5.54${\pm}$5.64 seconds, and the sample group stayed for 7.43${\pm}$6.09 seconds. The analysis of the memory retention data shows that the sham group marked more significant improvement stati- stically in memory retention compared with the control group(p<0.05).3. In the learning of radial arm maze, the number and rate of animals that arrive the learning criteria amounted 12 out of 14, 85.7% in sham group, 4 out of 13, 30.8% in the control group, and 10 out of 14, 71.4% in the sample group So, the sample group shows better learning capacity significantly compared with the control group(p<0.05). With the experimental results above, Hyungbangjiwhangtang can be supposed to have the improving effects on the learning and memory of AD rats induced by eletronical injury of nbM.