The lower boundary age of Mesoproterozoic is positioned at 1600 Ma by International Commission on Stratigraphy (ICS), and the global platform covers are formed at Calymmian with time span of 1600 Ma to 1400 Ma. The North China Platform entered an epoch of extension-broken after its consolidated at 1800 Ma. Then the Luliang Mountains area in Shanxi Province, the Zhongtiao Mountains in South Shanxi Province and the Xiong’ershan area in Western Henan Province are split into a trigeminal Aulacogen. The SHRIMP and LA-ICP-MS zircon ages of the volcanic rocks from Luliang Xiaoliangling Formation are 1763±42 Ma and 1779±20 Ma respectively; and the SHRIMP zircon ages have been obtained from Xiong’er Group in Western Hennan Province are 1776±20 Ma (dated for the volcanic rocks) and 1779±29 Ma. It seems reasonable to take the 1800 Ma as the lower boundary age of the Xiaoliangling Formation and Xiong’er Group. The rocks of Hangaoshan Group of Luliang Mountains area are siliciclastic with volcanic rocks, deposited at the same time with Xiaoliangling Formation, which suggest the quick filling of the north part of Luliang-Shanxi-Henan trigeminal Aulacogen. The Hangaoshan Group and the Dagushi Formation (sedimentary rocks deposited at the bottom of Xiong’er Group) are the sediment covers after the rifting at 1800 Ma, the mafic dykes related to the volcanic rocks from Xiaoliangling Formation and the volcanic rocks from the Xiong’er Group are the products of magmatism in the stage of broken-up. The Miyun rapakivi granites from Beijing are emplaced at 1700 Ma, which indicate the start time of the broken up of the Yanshan-Taihangshan Aulacogen and the lower boundary age of Changzhougou Formation, Changcheng System. The weathering crust, overlap the Miyun rapakivi granites, is dated at 1650 Ma, represents the time began to accept the deposits after the rifting of Aulacogen. It is not the age of the lowest layer in Changzhougou Formation. The age 1700 Ma and 1650 Ma are the lower boundary ages of different areas in Changzhougou Formation. but it’s not equal to the lower boundary age of Changcheng System or Mesoproterozoic. The lower boundary age of the Gaoyuzhuang Formation is 1600 Ma, as the boundary age of Changcheng System and Jixian System. It is not only the close time of Yanshan-Taihangshan Aulacogen, but also the end of the extension-broken time of North China Platform from 1800 Ma. The new epicontinental basin began to develop at this time, and the North China Platform experienced tectonic transformation. Therefore, the significant tectonic events affected North China Platform at 1800 Ma and 1600 Ma, which reflect great regional tectonic implications. According to the determination principle of Pre-cambiran boundary age, both the two ages are used to be the lower boundary of Mesoproterozoic. But in this paper, we approve of 1800 Ma as the lower boundary age of Mesoproterozoic, because of it’s more in line with the Chinese tectonic: 1800 Ma is the lower boundary age of the platform covers from the North China Platform to intra-craton Aulacogen. There are different tectonic settings of the basins in the North China Craton at Mesoproterozoic at different times: it is Aulacogen at 1800~1600 Ma, then develop to epicontinental sea at 1600~1400 Ma, at last transfer to arc-back basin at 1400~1300 Ma; 1800 Ma、1600 Ma and 1400 Ma are three time points of regional tectonic transformation at Mesoproterozoic.