Abstract: The pentatricopeptide repeat（PPR） proteins contain 2 to 27 tandem repeat domains, and each domain contains 35 amino acid residues. PPR proteins are a class of RNA-binding proteins widely exist in eukaryotes. They have sequence-specific recognition patterns for single-stranded RNA and are closely related to RNA transcription, shearing, editing, maintaining stability, and translation. So far, only seven PPR proteins have been found in mammals, all of which exist in mitochondria, including mitochondrial RNA polymerase（POLRMT）, leucine-rich pentatricopeptide repeat-containing protein（LRPPRC）, mitochondrial ribosomal protein of the small subunit 27（MRPS27）, mitochondrial RNase P protein 3（MRPP3） and pentatricopeptide repeat domain protein（PTCD） 1～3. Mammalian PPR proteins have diverse roles in mitochondrial transcription, RNA metabolism and translation and consequently are important for mitochondrial function and cell health. This review briefly summarized the structure of 7 menbers of the PPR protein family, explored the role of PPR proteins in regulation of mitochondrial gene expression, and looked forward to the application prospects of PPR proteins for human mitochondrial-related diseases.