A microsatellite is a short, repetitive sequence of DNA (usually 2 to 4 nucleotides in length). Multiple primary lung cancers (MPLC) are more than one primary lung cancer lesions arising synchronously in different locations of the same or different side of the lung. These neoplasms may have same or different histological types, but one lesion is not a metastasis from another, as each neoplasm arises independently in the lung. Abnormal microsatellite changes are closely related to the pathogenesis and development of MPLC. In this review, several aspects are discussed:①definition and origin of microsatellite; ②abnormal changes of microsatellite; ③definition and categories of MPLC; ④the influence of microsatellite on early diagnosis, treatment and prognosis of MPLC.