It is a major national strategy to plan the construction of the Beijing's Sub-center，to dispel the function of Beijing's non-capital，and to promote the coordinated development of Beijing-Tianjin-Hebei.Since ancient times，Tongzhou has assumed a part of the administrative functions of the capital Beijing and made important contributions to the protection，construction，prosperity and stability of Beijing.Under the pattern of the combination of the main and the deputy，Beijing's Sub-center not only has the historical responsibility to promote the non-capital function mitigation and promote the coordinated development of the Beijing-Tianjin-Hebei region，but also inherits some functions of the capital science and technology innovation center and cultural center，becomes a new growth pole of the capital science and technology innovation function and cultural function，and optimized the spatial layout and development mode of the capital function realization.Judging from the political function orientation，legal nature status and urban development goals of the Beijing's Sub-center，the sub-center legislation involves the capital function and the coordinated development of Beijing-Tianjin-Hebei，and its legal status，management rights，and influence scope are beyond the legislative power of Beijing. On the basis of investigation and demonstration by the Standing Committee of the Beijing Municipal People's Congress，it should be incorporated into the central capital's legislative system，directly legislated by the Standing Committee of the National People's Congress and the State Council，or authorized by the Standing Committee of the National People's Congress and the State Council.