This is a study in one group of primary 6 students that studying in Thai language at Saint Gabriel’s college of Thailand. It aimed to find out what is the current situation of primary 6, what are the appropriate OD interventions, does OD intervention have initial impact on, and compare the different between students’ attitude, teaching strategy, and teachers’ competency when we use the application of Thai folk songs in learning Thai language. Moreover, this study also hoped to discover the advantages and disadvantages of the application of Thai folk songs in learning Thai language and then to determine which assessment system was more preferable.