China’s outbound tourism boomed during the several years from the end of 1990s to the beginning of the twenty-first century,with an annual growth of over 20％.In 2002,China’s outbound tourists reached 16,600,000,surpassing that of Japan (16,520,000) for the first time,and China thus became the largest source in Asia.This was also the transition stage during which per capita GDP increased from US $1,000 to US$ 2,000.Although outbound policies have important impacts on outbound tourism,the final determinant is economic,namely,effective demand.Some scholars believe that China has reached a new phase of tourist consumption.Some even propose that outbound tourism demand increases rapidly when GDP reaches $1,000,and intercontinental tourism demand surges when per capita GDP reaches $3,000.However,the authors hold a different view.This paper compares the developments of outbound tourism from Japan,South Korea,and Taiwan,and finds that:(1) the threshold value of outbound tourism explosion occurs when per capita GDP and per capita income approaches $10,000;(2) surpassing $10,000 is a prerequisite for the period if steadily increasing outbound tourism.Based on a comparison of the relationship of tourism development and economic background,the paper proposes that China’s outbound tourism has outpaced economic growth as the result of income polarization.