Abstract: Biological invasion is a worldwide ecological phenomenon, but its mechanism is still not very clear.Invasive species give impacts on native species and ecosystems through competitions, predations, changing habitats, and dispersing diseases.They pose an increasing threat to the composition and structure of natural communities across the globe.Biological invasion has been greatly damaging the ecological and evolutionary integrity of natural e-cosystems, which will weaken the functions of the ecosystems and frequently cause natural disasters.Abetter understanding of the causes, patterns, predictability, consequences, and management options associated with this threat to biodiversity is necessary to guide managers, policy makers, researchers, and general publics.Biological invasion also causes huge economic losses, and 137 billion dollar losses per year from biological invasion were estimated in USA.Invasive diseases impair human health and kill thousands and thousands of people, and invasive bacteria lead to so serious social panic and turbulence that people could feel uneasy even when eating and sleeping.Biological invasion largely decreases global biodiversity, which will threaten the survival and development of our descendants.Three steps are used in prevention and control of biological invasions.Comprehensive quarantine is the most effective way to prevent exotic invasion by accident.Ecological evaluation and monitoring is helpful to avoid disasters from species introduction.Physical methods, chemical approaches and biological controls are used to eradicate and control the spread of invaded species.Before biological controls are chosen, risk analysis of controlling organism is needed.Ideally, there should be both pre-eradication assessment to tailor removal to avoid unwanted ecological effects and post-removal assessment of eradication effects on both the target organism and the invaded ecosystem.