The Manas River is the largest stream in the north margin of the Tianshan Mountains and tectonic activity has distinct influences on the landform in the north margin of the Tianshan Mountains.Based on the filed survey and analysis,the result shows that north-west compression resulted in three rows of folding in the northern piedmonts of the Tianshan Mountains and also is responsible for the fourth fold of the Xihu which is still developing.Every anticline is steep in the northern limb and gentle in the southern limb.The ages of three folds become younger northward,while the altitude and range of the three folds decrease correspondingly.Three fans developed in the shape of cluster,and are controlled obviously by reverse faults.Terraces were warped and faulted by tectonic deformation of the second-class and the third-class folds,indicating that the Tianshan Mountain has been uplifting since Quaternary period,and its compression toward north from sough is causing the piedmontis to continuously expand toward the Junggar basin.