【Abstract】ObjectiveTo discuss the molecular structures and functions of Alu repeats,and its relationships with malignant tumors. MethodsAdvances in molecular biology and oncology of Alu repeats in recent years had been reviewed. ResultsHomologous recombination between Alu repeats may result in various genetic exchanges,including duplications, deletions and translocations,cause a series of malignancy alteration by activating some oncogenes. ConclusionAlu repeats as a sort of multifunction regulatory sequences may play an important role during the carcinogenesis and progression of some tumors.