Minimal Surface System is a higher codimension analogue of Minimal Surface Equation in codimension one. The Dirichlet problem for codimension one Minimal Surface Equation has general existence, uniqueness, stability and regularity results, however all these fails in higher codimension. In this talk, I will discuss a recent joint work with Yng-Ing Lee and Mao-Pei Tsui on the higher codimension uniqueness problem in certain convex classes.