本文主要藉由楠梓仙溪流域的階地及沖積扇等地形之階地特徵及分布的調查，將楠梓仙溪流域的河階資料做一整理，並進行個別階地及流域上、下游階地的對比，重建楠梓仙溪流域之河床高度的垂直變動過程，進而推論影響此區地形演育的可能因素。在重建的過程中，由於此區缺乏定年資料佐證，在年代的判斷上僅能以流域內發現的紅土臺地面做為參考的依據。 本研究的範圍在階地地形特徵較為明顯的三民鄉至杉林鄉的主流側階地，階地的分布以「小林峽谷」為界，分為上、下游二區，上游區連續較佳，以沖積扇階及岩石階地為主，下游區自甲仙以下的階地連續性較佳，以岩石階地為主。上、下游階地發育期皆可分為四期。在階地分布及古河床高度的垂直變動過程中有以下特徵：(1) 階地多分布於本流東側；(2) 階地類型的分布在上游區以沖積扇階地為主，下游區則較多岩石階地；(3) 上、下游階地發育時期大致可分為四期，前二期均發育有岩石階地及沖積扇階，後期二期以岩石階地的發育為主，局部地區發育有小規模的礫石階地；(4) 在河床高度的變化方面，前二期具有較大規模且下切與加積量均大的變動；(5) 流域的最近期河流持續下切，河床的高度呈現下降的趨勢，目前應持續進行下切作用。

The aims of this study are to investigate and analyze the river terraces and alluvial fans of the Nantzuhsien River basin in Kaohsiung, southern Taiwan. We will: (1) characterize the Nantzuhsien river terraces based on field data, (2) reconstruct the history of behavior of the Nantzuhsien river, (3) interpret and discuss the geomorphic evolution of the Nantzuhsien drainage basin. The upper and lower reaches of the Nantzuhsien River are divided by the Shiao-lin Gorge. The terraces of the upper reaches, mostly alluvial fan terraces and strath terraces, are marked by continuity. The terraces of the lower reaches are mainly strath terraces that, are fragmented except for those developed downstream from Jia-shian. Field evidence shows that there are four stages of terrace development in this area, and their characteristics include : (1) river terraces are developed mainly in the eastern part of the drainage basin (2) the alluvial fan terraces are mainly developed in the upper reaches, and the strath terraces are mainly developed in the lower reaches, (3) four stages of terrace evolution can observed, with strath terraces and larger fan terraces found in the two earlier stages while only strath terraces are developed in the two later stages, (4) the height of the bedrock and the river downcutting show greater variations in the two earlier stages (5) the process of river downcutting is still progressing today.