In order to encounter the necessities of the application, cross-linking of poly(methyl methacrylate) (PMMA) has been emerged and become an interesting issue, due to the unsatisfied results that result by the neat poly(methyl methacrylate) itself. Numerous facets make cross-linked PMMA superior and preferred than uncross polymer like the enhanced heat performance, the outstanding mechanical properties, its chemical resistance and good abrasion resistance. UV radiation, Cross-linking by free radical, small-molecule cross-linking, and condensation are discoursed concisely in the following review, also the effects of cross-linker on polymer properties are discussed. Importantly, present the review discusses the different important applications of cross-linked PMMA.