This research considered the characteristics of Credit Departments of Farmer’s Associations in Taiwan to establish Slack-Based Measure Data Envelopment Analysis Model (SBM-DEA) for analyzing the operating efficiency of Credit Departments of Farmer’s Associations in Taiwan. Because “Agricultural Bank” plays an important role for Credit Departments of Farmer’s Associations in Taiwan, this research also analyzes the effect of establishment of the Agricultural Bank. Finally, this research compares the differences of DEA with SBM-DEA model.