本研究探討我國銀行業授信資產品質與經營績效之縱橫平滑移轉效果，運用Gonza’lez, Teräsvirta and Dijk（2004, 2005）之縱橫平滑移轉迴歸模型，驗證銀行授信資產品質對經營績效是否存在縱橫平滑移轉效果。並進一步對銀行經營績效受控制變數之影響進行評估與衡量。 實證結果發現，逾期放款比率對銀行每股盈餘及淨值報酬率分別在逾期放款比率為3.233%及2.939%時產生一轉換區間，確實存在縱橫平滑移轉效果。 控制變數對銀行經營績效之影響方面，逾期放款比率相對處於低檔之銀行，覆蓋率愈高，每股盈餘及淨值報酬率下降，擴大營業或資產規模則反之。 逾期放款比率相對較高銀行，淨值成長率或負債比率愈高，以每股盈餘及淨值報酬率衡量之績效表現愈佳，反映面對高風險放款資產且以高財務槓桿型態經營之銀行，能提高每股盈餘及淨值報酬率。 不論逾期放款比率高低，資產規模愈大之銀行，以每股盈餘及淨值報酬率衡量之績效表現愈差，此結果與目前銀行業現況大致相符。故建議銀行管理當局及經營者應視不同之逾期放款比率水準，擬訂妥適之管制機制或經營方針，以求取最佳化策略。 This study is to investigate the panel smooth transition effect associated with quality of asset credit extension and operating performance of banks in our country. Utilizing the panel smooth transition regression model developed by Gonza’lez, Teräsvirta and Dijk (2004-2005), we test whether the quality of banking credit extension can cause panel smooth transition effect on management performance. We further extend the model strategy for evaluating effects of the controlling variables on bank operating performance. The results showed that a transition period is generated when the overdue loan ratio falls between 3.233% and 2.939%. Therefore, overdue loan ratio does affect earning per share (EPS) and return on equity (ROE) of banks, and reveal the characteristic of panel smooth transition effect. We also examine the influence of controlling variables on banking performance. For the banks with lower overdue loan ratio, higher covering rate results in reduction of EPS and ROE. On the contrary, expanding business or capital estate scale leads to the opposite consequences. For the banks with higher overdue loan ratio, the higher equity growth rate or D/A is, the better performance (evaluated by EPS and ROE) they have. This reflects why the banks running at high loan risk and high financial leverage can still promote their EPS and ROE. Regardless of high or low overdue loan ratio, banks with greater asset scale perform unsuccessfully in terms of EPS and ROE. This result conforms to the current situation of banking industry in our country. Therefore, our studies suggest that administration authority and bank managers adopt appropriate control machinery or operating strategies according to different overdue loan ratios, in order to come up with the best policy.