This research aimed to develop the instruments of Mathematics instructional by using caring community-based learning cycle 5E on “Matrix Operations” Learning Material for the eleventh grade students of senior high school as well as to know its effect on the student’s mathematical communication skill. The research method used in this study can be considered as a combination of qualitative and quantitative methods. Qualitative methods are used to obtain data related to the results of the development of learning tools and quantitative methods are used for statistical analysis. The research subjects were the students of SMAN 1 Tegaldlimo, Banyuwangi Regency, from which three classes were chosen as the research samples, class XI MIPA 4 as the control class and class XI MIPA 5 as the first experimental class and class XI MIPA 2 as the second experimental class. Mathematical communication skill was measured by using the essay test. In the normality test, the data obtained were normally distributed and the data were homogeneous based on the homogeneity test, so that it was necessary to do the parametric data analysis by using One-Way ANOVA analysis. The results of the research showed that: (1) the instructional instrument resulted was valid, the implementation of the instructional instrument was practical and effective; (2) the significance value (2-tailed) was 0.000 (p < 0.0-5), which indicated that the application of learning by using caring community-based learning cycle 5E had a significant effect on the student’s mathematical communication skill.