Based on the detailed research on outcrop the s ections of the Devonia in Zen'an Basin, South Qinling, the Devonian can be divided into four depositional systems, i.e coast system, carbanate system, self system and slope—basin system, with the characteristics that depositional systems and litofacies aemblages are different from on the belt to another through north to south while extending west to east in spatial. In terms of the strata overlaping froms out to north and the trend of facies type scanging from distal facies in the south to proximal facies in the north and terrigenous sediments transported from north to south, there souldbea disappeared ancient land in the north. According to the evolution of depositional systems and litofacies aemblages, the history of the Devonian depositional basin can be divided into three main evolutionary stages, with careinitial depretion period, depressional period and strong rift faulting period, their paleogeographic pattern was varying with in different stages. From north to south it displayed the pattern so fancient land coast self in Givetian stage in Mid Devonian, ancient land carbonate flat self in Frasnian stage, and upliftcoastselfslopebasinflat in Famennian stage in Late Devonian.