The Yixi River is a primary tributary of the Shaxi River, which is upper tributary of the Minjing River, valley geomorphology of the Yixi River is more representative in Fujian Province.Methods: In this study, we completed a Quaternary broehole (GC4) with Quaternary 22.4 m in the source area of the Yixi River, analyzed sedimentary environment according to AMS14C, Grain- size and magnetic susceptibility. Discussed sedimentary environment in the source area of the Yixi River and development process of the river implications by comparison of regional lithostratigraphy and characteristic of valley geomorphology.Results: GC4 was divided to 5 sedimentary stages from middle of Late Pleistocene till now: fluvial facies, limnetic facies, weathering lacustrine facies, pluvial facies and fluvial facies. Sedimentary discontinuity happened in later Late Pleistocene.Conclusions: Sedimentary environment in the source area reflected regional neotectonic movements were as follows: uplift, sinking, steady, uplift rapidly, sinking first and then sinking, uplift durably, corresponding valley geomorphology consisted in in the source area, upper and middle of the Yixi River. The river appeared in middle of Late Pleistocene, valley geomorphology completely developed in middle of Holocene. The most rapidly uplift occurred in later Late Pleistocene.