The instruments employed to collect data were 3 Thai language lesson plans of Pratomsueksa 3 around the topic Reading and Writing Thai Leading Alphabets by using Supplementary Exercises with Brain Based Learning Technique and a 30-item achievement test which has the discrimination index from 0.21 to 0.82 and the total reliability of 0.87. The collected data were analyzed by percentage, means, standard deviation and effectiveness index.