汉魏之际，杂部密教经典已传译于中土。入唐以降，密教开宗立派，活跃于朝野上下，虽经“会昌法难”之劫而渐趋式微，但随着密教的世俗化已渐次深入民间，化俗流布。其中，民间流行的五色线习俗，即与民间传持的密教相互影响。自汉代以来，古人就有端午时节佩戴五色线用以避兵驱邪的习俗，其发端虽与中国传统的五行学说有一定关系，但入宋以后，密教大悲咒在吸收五色线元素后，又与五色线习俗相融合，并将其供奉主神之一的“月光菩萨”良缘功德赋予五色线。这一功德的加持，使五色线习俗发展到宋代时，已经由端午佩戴延长到七夕，一些地方甚至由此演变为“女儿节”。 考研这一习俗的历史演变，不仅有助于再现唐宋时期民间特殊的人文风貌，同时对于研究唐宋时期的社会生活与宗教信仰也具有一定的参考意义。

Tantric Buddhism Sutra was firstly translated into Chinese and spread in China in the late Han and early Wei Dynasties. In the Tang Dynasty, Tantric Buddhism school was founded and its practice was widely accepted by both government officials and common people. Although it was greatly weakened due to the catastrophe that Buddhism suffered during the period of Huichang in the Tang Dynasty, Tantric Buddhism, with its secularization, had penetrated into the daily life of common people. For instance, the custom of five-color strings and the folk practice of Tantric Buddhism impacted upon one another. Influenced by the doctrines of Five Agents, there had been the custom of wearing five-color strings to avoid and drive out evil spirits in the Dragon Boat Festival since the Han Dynasty. However, in the Song Dynasty, it was combined with the Great Compassion Mantra of Tantric Buddhism and then Candraprabha, one of its main Buddhas. With such enchantment, people began to wear five-color strings not only in the Dragon Boat Festival but in the Double Seventh Festival as well, and this custom was even transformed into the “Daughter’s Festival” in some places. A historical study of this custom helps us not only represent the special folk culture in the Tang and Song Dynasties but also understand better the social life and religions at that time.