According to Dr. Gong Weizhang, a locally developed calendar had been put into use in the Dunhuang region prior to the Tibetan Occupation. On the basis of a lot of signatures on Dunhuang documents as well as inscriptions, this paper argues that the calendar used at Dunhuang prior to the Tibetan Occupation was still the one issued by the Tang court. As far as the research methodology is concerned, we should gradually revise and improve the calendars made in later times according to unearthed materials rather than using these calendars as the only standard to justify the unearthed dated materials. A table of the Linde Calendar of the Tang dynasty edited by Huang Yinong, professor at Tsinghua University in Tanwan and academician of Academia Sinica, is at the end of the book for reference.