In the process of building the ballastless track of the high speed railway from Wuhan to Guangzhou, the measuring method of the CPⅢ control network has played an extremely critical role. In this article, the form layout, measuring method, precision requirements and some other contents of the high speed railway ballastless track CP Ⅲ have been proposed. It has been proved that this control network has reliable technology basis and meets the construction requirements, which is available for other similar engineering.