The age of Cambrian lithostratigraphic units in eleven areas of northwestern China, including the Tarim, middle Tianshan, Altun Shan, Bei Shah, northern Qaidam, southern Qilian, northern Qilian, middle Qilian, southern Qinling, southern Hanzhong, Ordos, and North China, are considered under the new global/Chinese Cambrian framework with four epochs and ten ages. This study would provides new insights into stratigraphic subdivision and correlation of the Cambrian System of northwestern China.