A small butterfly flapping its wings over a certain place disturbs the air, which may cause a storm in a distant place for a long time, which is a metaphor for the unpredictable and serious consequences caused by a small factor in long-term large-scale weather forecast. Small deviations are inevitable, which makes long-term weather forecast unpredictable or inaccurate. This is like playing billiards, chess and other human activities, which are often "a thousand miles away, a tiny difference" and "one careless move will lose the game." Long-term large-scale weather forecast is the observation, calculation, analysis and judgment of the complex system of the earth's atmosphere, which is influenced and restricted by many factors that change at any time and place. It can be considered that the prediction of its comprehensive effect is difficult to be accurate and the butterfly effect is inevitable. Our human research objects also involve other complex systems (including "natural systems" and "social systems"), and their internal constraints are also complex, and their "butterfly effect" is inevitable. "Today's butterfly effect" or "generalized butterfly effect" is not limited to the original Lorenz butterfly effect, which is only used for weather forecasting, but is synonymous with all complex systems being extremely sensitive to initial values, which means that for all complex systems, under certain "threshold conditions", their long-term and large-scale future behaviors are extremely sensitive to small changes or deviations of initial conditions, that is, small changes or deviations of initial values will lead to huge future prospects. Butterfly effect refers to a very small change in initial conditions, which will have a great impact on its future state after continuous amplification. Some small things can be confused, and some small things are very important to an organization and a country if they are amplified by the system, so we can't confuse them.