The second wave of the COVID pandemic has lower impact on the world economy as the research for vaccine and the inoculation have made encouraging progress. Moreover，fiscal and monetary policies adopted by various countries to alleviate the pandemic have promoted economic recovery to some extent. The instability of the pandemic，the repercussions of the expansionary policies，unsolved problems existed before the pandemic，and the future policy adjustments of major economies constitute short-term factors affecting the world economy trend in 2022. Medium and long term factors include the record high debt level，aging population，sluggish labor productivity growth，the multilateral trading system reform，lockout at WTO’s appellate body and the difficulties to reach consensus on reform negotiations，persisted financial regulatory loopholes，economic nationalism especially resource nationalism. This paper believes that global economic growth rate will be around 5.5% in 2021，and will likely to drop to 4.5% in 2022.