In 21th century, AsiaPacific RTAs have been increased dramatically, which is a paradox between the theory and the reality. This inspires researchers to search for the reasons behind it and new method to study it. For the first time, this paper examines which effect is more important, RTA quantity or RTA quality. Through comparative analysis of developed and developing countries, we find why developed countries improve trade agreement rules in the new era. Comparing each clause in RTA, we measure RTAs quality by the coverage and statutory commitment rates in the WT+/WTOX areas. The empirical test shows that signing high quality RTA has significant positive effect on the AsiaPacific countries economic growth and welfare. The effect is more significant among developed countries. However, the effect for developing countries is not obvious because of their limited executive ability.