「降低班級學生人數，實施小班教學」是當前教育改革最熱門的課題，這項政策的實施，可以增加師生互動的品質和數量、提高學習的成效，尤其是美國方面的實驗證明，小班教學對低年級學生的學習成效尤其明顯。 我國自一九九○年代以來，小班教學也成為朝野共同關心的教育議題，教育部更在《中華民國教育報告書》中明確指出「降低班級人數至三十五人」顯示政府降低班級人數的企圖心。 然而，我國自確立降低班級人數開始迄今屆滿三年，但卻成效未臻顯著；本研究乃以文獻分析為主，並輔以比較研究，希望了解美國降低班級學生人數，其有關政策與推動方面之優點，作為我國小班教學政策改進的參考指標之一。 本研究發現，可以歸納如下： (一)降低班級學生人數政策是中、美兩關重要的教育改革課題； (二)我國國中班級平均學生人數高於三十五人，有九個縣市； (三)我國國小班級平均學生人數高於三十五人，有一個縣市； (四)我國國中班級平均學生人數低於三十三人以下，有四個縣市；國小低於三十人以下，則有九個縣市； (五)中、美兩國降低班級人數政策之做法有些差異，而美國的作法頗具參考價值。 最後，根據研究發現，對於教育行政機關提出五點建議。

Class-size-reduction (CSR) is currently one of the most popular issues. Experiments in the United States provide the evidences that CSR increases both the quality and quantity of interaction between teachers and students, and improves students' achievement, especially junior students. CSR has also become a common concern to the public and the government since 1990. The Ministry of Education even attempted to reduce class size to 35 explicitly in the "The Educational Report of ROC". But so far the outcome of CSR has not come up to a complete satisfaction. This study was mainly based on literature review and aided with comparative analysis. It is hoped that this study helps to realize how CSR works in the US, and how its advantages can be one of the reference indexes of improving CSR policy in our country. According to this study, the followings are reached: 1.CSR policy is one of the most important education reform topics for Taiwan and for the United States. 2.There are 9 counties (or cities), of which junior-high average class size is above 35 in our country. 3.There is one county (or city), of which primary students' average class size is above 35 in our country. 4.There are 4 counties (or cities), of which junior-high average class size is below 33 in our country, and there are 9 counties (or cities), of which primary students' are below 30. 5.There are differences between CSR policy of R. O. C. and CSR policy of the United States. The US CSR practices are of considerable implication to CSR policy in ROC. Based on this study, some suggestions are presented for educational administration authorities.