Terraces in tectonically active mountains and uplands record both tectonic uplift and climatic changes. The author discusses the methods of how to distinguish the role of both tectonic and climatic factors. Fluvial system in inland is a process of reaction between aggradation and incision controlled by tectonic movement or climate changes. Through studying the cause of formation of terrace, point out that climate-controlled terrace mainly deposits in the glacial period, and incises during glacial-interglacial transition. Incision of tectonic-controlled terrace takes place in active phase. At the same time, the palaeo- channel begins abandoning. People can determinate the cause of terraces through geology features analysis and contrast them with others that were put forward before. Every one of climate- caused terraces reveals that there is/are one/several glacial to interglacial cycle(s), the gravel interbedded with slope deposition, the declining terraces bottom; while every one of tectonic-caused terraces implies that there is a tectonic event during its formation. Some terraces result from both tectonic movements and climate changes.