The opening up of regional economy is a kind of dual opening up. It is opening up internationally, and opening towards other regions in the same country. Many researchers have measured international openness for existing systemic data, but no one has measured interregional openness because of data lacking. From the perspective of provincial economies in China, this paper tries to construct a set of indicator system to measure interregional and international openness in terms of comparatively wide meanings of openness, attempts to measure the dual openness of the main provincial economies in China and grasp their opening characteristics.