The purpose of this study was to investigate the effectiveness of using thinking maps on algebraic problem solving and mathematical communication of eighth grade. The sample of the study consisted of (65), grade eight students from one school which located in Muscat Region. The students were distributed in two groups, the experimental group, which was taught using thinking maps, and the control group which was taught in the ordinary way (the normal practices and instructional methods of the teacher). The researcher selected one math unit of grade eight math book. The study lasted for 4 weeks, 7 periods of 45 minutes per week. At the end of the study the researcher applied the algebraic problem solving test and the mathematical communication test on both groups. The means and standard deviation of the two groups were calculated, T-Test was used to verify the significance of difference between the mean scores of the study groups. It was shown that: . There was a statistically significant difference at (a < 0.05) in the algebraic There was a statistically significant difference at (a < 0.05) in the mathematical communication test in favor of the experimental group. Based on these results, the researcher recommended to using maps of thinking in mathematics teaching, re-organizing mathematics textbooks by using thinking maps, and clearly defining the relationships between different mathematical concepts, to facilitate their acquisition process.