The objective of this research is undertaken to see whether the deductive method in teaching English grammar by using the group work technique has a positive effect on the academic achievement of the students of Dual System Class B at Politeknik ATI Makassar, expecially for students. Using deductive method with the help of group work played a positive role in improving the academic achievement of students who studying English at Dual System class. This method with the help of group work has improved the score Pre-test (60.9000) and Post-test (86.2000). This method also can improve students’ grammar in use, motivate students in learning grammar and as an effective method in teaching grammar. This research as also change what people think that deductive method often make the learners’ role rather passive as much of the attention is only focused on the teacher explaining the rules and showing the examples.