Matrix theory plays a very important role in teaching Mathematics and solving mathematical problems. Studying the theory of matrix can help academics, practitioners, and students solve many problems in Engineering, Econometrics, Finance, Economics, Optimization, Decision Sciences, and many other areas. To review the matrix theory with applications, in this paper we first review the theory of matrix. We then discuss how to build up some mathematical, financial, economic, and statistical models by using matrix theory and discuss the applications by using the theory of matrix in Decision Sciences and other related areas like Mathematics, Economics, Finance, Statistics, and Education with real-life examples.