The drug industry of China is faster than before, so it will rank 5th at world-wide markets in 2010. This is because of expansion of purchase power on increase in economic growth, extended human life expectancy. As it is entered the WTO in January 2002, it will positively affect on export of Korea for China. This paper focuses on the analysis of export increase caused by reduction of custom tariff in China. The time schedule on average reduction of custom tariff is 15% in 2000, 10% in 2005, 5% in 2010. As the empirical test, it presents 8.48% export increase rate for China of Korea on reduction of custom tariff.