This Classroom Action Research (CAR) aims to overcome the low understanding of algebraic concepts and anxiety by applying the CPA math word wall group competition. CAR is carried out in 3 cycles. CAR is imposed on 32 7th grade students of SMP N 12 Purworejo. The research instrument used observation sheets and essay tests. The data analysis technique used a paired sample T-test to see an increase in concept understanding. The results of the study indicate that the application of CPA math word wall group competition can improve students' conceptual understanding.