The basic framework of "The Buddha-spoken Ullambana Sutra" offered the story framework for Mulian Rescues His Mother and underlay the abundant connotation for Transformation Text on Mulian Rescuing His Mother from the Underworld when transformation texts on popular lectures by temples flourished during the Tang Dynasty. Today there are three different systematic stories circulating that have already been well known. It shows particular emphasis laid respectively on the development for contents of popular lectures, coupled with signs of literati's polishing, that sees the popularity of this well-known story. This essay conducted in three aspects. It starts with the narrative form to show that Transformation Text on Mulian Rescuing His Mother from the Underworld feature contents of popular lectures by temples. Lectures were given in an accompaniment of images, and it's thus evident that Transformation Text on Mulian Rescuing His Mother from the Underworld is not a branch of work knowledge about one time, one place or one person. The second part focuses on the application of folk literature to the discussion of the literariness of Transformation Text on Mulian Rescuing His Mother from the Underworld. The third aspect is about folk customs displayed by contents of Transformation Text on Mulian Rescuing His Mother from the Underworld and formed from the further application of transcribing transformation texts.