Abstract: Based on the theory of business cycle and economic growth, the recent five Olympic host countries are taken as the research objects to compare the economic data of 35 countries from 2000 to 2018 with the synthesis method. It claims that: Only the Beijing Olympic Games played a positive role in China's long-term economic growth, while the Sydney Olympic Games' contribution to Australia's economic boost delayed for four years; The Athens Olympic Games powered Greece's economic development in six to seven years after the event, but it fell into a huge crisis due to the burden of the Olympics; The London and Rio Olympics helped to speed up the economy during the bidding period, but they actually slowed down the overall economy in the 3-4 years before the official games. The conclusion is drawn that there exists significant differences of long-term economic growth among various countries. The major channels of hosting Olympics to impact the economy include local consumption, regional investment, foreign trade, natural environment and social development, but only the moderate intervention from a capable government can effectively push the channels above to reach a positive result.