Abstract: Existed researches proposed that, trans-regional assistance after extremely serious earthquakes in China is an effective methodology to assist reconstruction after extremely serious disasters in unitary countries. However, as the providers were governments with higher administrative hierarchy, meantime it is questioned that its planning decision making may reveal tendency which was against localization of affected place. According to the above questioning, this paper studied the case of Shanghai assisting Dujiangyan City. By analyzing the characteristics of trans-regional assistant projects and corresponding other projects in project composition and geographical distribution, this study tried to reveal the decision-making tendency of assistance provider in two important aspects of settling down reconstructive projects and selecting sites. Advantages and shortcomings of the tendencies are discussed to provide references for the improvements of trans-regional assistance of post-disaster reconstruction after extremely serious disasters in China.