The main aim of this thesis is to collect and study critically the substance of Phleng Luk Thung involked in Buddhist Dharma since the glorious time of its in 2507 B.E. At that time, folk songs or country music have been titled as “Phleng Luk Thung” Moreover, it is to study the source of Thai tradition, custom, valuation, virtue, moral, the way of life and faiths of rural or pastoral people as found in Thai folk songs-Phleng Luk Thung.
          Luk Thung songs, Thai cultural heritage, have always reflected social status of any age, recorded historical scenes or events for later generations in order to acknowledge and inherit the good things. Although the substances of Phleng Luk Thung are various of love and departure and accusation of love but some of the songs are ended in the course of “The circle of action” man acts a good thing gets a good thing ; man acts a bad thing, gets a bad thing.
           If a subline religion is without an agreement and a well-behavior, people will be difficult to approach an art. It the art is not concerned with the religion, it will be degenerate, inelegant and indelicate. Therefore, all art and religion have a similar principle concerning emotion and mental conception in which they have mutual relationship.
           The substances of the research are to study critically Phleng Luk Thung concerned directly and indirectly with Principle of Buddhism as found in the songs. It includes criticism, conclusion and proposal of the substances.
           The research can be concluded as following :- Phleng Luk Thung is a precious literary works of the widely social status and the way of life of rural Thai people. The effect of general faith of Thai people for Buddhism has been found widely in Phleng Luk Thung. The belief in merit and evil makes the space between rich people and poor people spare or scares.  Phleng Luk Thung have always reflected “The symbol of Thai people” – The belief in merit and evil, previous existence and future existence. Although the belief is not science but it is an excellent consolation for some poor people steeped in despair and Phleng LukThung have also reflected almost Thai social which is short of an organization involved equality and justice. This may be considered that Luk Thung songs are not only the refined entertainments but also the literary works for more lives, in which Thai tradition and culture in the past are included for descendants.