The purpose of this study was to investigate the effectiveness of the use of expansionist theory in academic achievement among a sample of students of the fourth grade of primary education, has the researcher analyzes the content of the first three units to book social studies for students in the fourth grade of primary education, and reorganize content according to the steps expansionist theory, and Setup Guide teacher, has also set up academic achievement test, and after confirmation of the validity and reliability of the tools, the researcher apply to is made up of 30 pupils experimental sample, and carried by comparing them with a control group that the number of members 30 pupil, and found the results of the study into the effectiveness of the use of expansionist theory at every level of academic achievement on the immediate end "to remember and mouth and Application" At levels as a whole levels, also proved to be effective on academic achievement deferred.