As a convex method, LMI becomes more and more important in control field.First, this paper summarizes characteristics and uses of LMI.

• 由于内点法等算法日益成熟，并成为解决LMI问题的强有力的工具，线性矩阵不等式方法在控制理论中得到了越来越广泛的应用和发展。