As mathematics educators, the student's learning has been our major concern for long. Since many past researches were conducted in small-scale and limited in a validity of inferences, this research has been expanded into a larger scope to see if there could be changes between variables or mediators. It aims to re-conceptualize the self-concept and learning strategy on mathematics. It tries to facilitate the classroom teaching direction in the future, and to design a quality self-concept enhancement program for students. With the questionnaire survey used in this study, the instruments included the mathematics self-concept scale and the mathematics learning strategy scale. Then, the structural equation modelling was used to analyze the data (N=1,200) from the 8^(th) graders in Taiwan. The findings from this research are consistent with the previous studies on (a) mathematics self-concept has a significant positive effect on mathematics learning strategies; (b) mathematics self-concept has a significant positive effect on mathematics academic achievement; and (c) mathematics learning strategies has a positive effect on mathematics academic achievement. Mathematics learning strategies are proved to be able to play as the mediator toward mathematics academic achievement in this study. Unlike previous researches, mathematics learning strategies should include cognition strategies, recognition strategies, and resource management strategies. Teachers need to be aware of the mathematics learning strategies for timely change and need to be flexible when using teaching strategies. The implications for the present study were discussed and the suggestions for teachers and further research were also proposed.