Abstract: Guanine nucleotide-binding proteins (G proteins) are crucial in the regulation of both intercellular and intracellular signal transduction.Structural mutations in and the dysfunction of G proteins are common molecular pathological mechanisms in many diseases.The α-subunit is the structural and functional center of a G protein.Pseudomyxoma peritonei is a malignancy involving persistent mucin secretion.Structural and functional mutations in the Gα protein result in the continuous secretion of mucus, an important molecular pathological mechanism of pseudomyxoma peritonei.This review summarizes the expression pattern of the Gα gene, the structural and functional changes in the Gα protein after mutation, and the relationship between Gα mutations and pseudomyxoma peritonei, in order to explore the molecular pathological mechanism of pseudomyxoma peritonei.