Rett syndrome (RTT) is an X-linked neurodevelopmental disease accountable for some of the severe mental retardation of females. Mutations in the gene encoding mythyl-CpG-binding protein 2, MeCP2, which acts as a suppressor of gene expression, are the primary genetic pathological change of RTT. Insufficient binding of MeCP2 with methylated DNA disrupts the proper expression of target genes and results in brain dysfunction. Currently, the proper role MeCP2 played in the process of brain development and the occurrence of RTT remain elusive. In this review, we summarize both the MECP2 gene and MeCP2 protein, with highlight upon their structures, functions and more importantly their regulatory mechanisms at the molecular level so as to elucidate the mechanisms underlying the pathogenesis of RTT.