An early warning system for monitoring deep hole tension type multipoint displacement and a construction method belong to the field of safety early warning for rock stratum deformation displacement monitoring. The system is composed of an anchor head, a steel wire tensioning wire, a displacement data acquisition instrument concentrating disc, a solar storage battery, a wireless signal emitting device, a computer data processing terminal and an early warning system. When rock stratum sedimentation happens, data acquisition can be conducted on displacement increment through the displacement data acquisition instrument on the displacement data acquisition instrument concentrating disc. Acquired data are transmitted to a computer data processing terminal through the wireless signal emitting device, and the data are fed back to the early warning system after being processed. The early warning system can transmit an early warning result to a mobile phone through a wireless network to achieve the aim of safety monitoring and early warning. The early warning system for monitoring the deep hole tension type multipoint displacement and the construction method are used for monitoring the displacement increment of a rock body along the axial direction of drill holes, at most twenty monitoring points can be arranged in each drill hole, the largest drill hole depth can reach 600m, and the early warning system for monitoring the deep hole tension type multipoint displacement and the construction method are particularly applied to monitoring early warning of ground surface settlement induced by large underground excavation engineering of coal mining and the like.