A wireless low-power safety monitoring acquisition system is developed by adopting LoRa communication, coprocessor and spectrum analysis to tackle the problems of scattered location of measuring points, danger of working condition, difficulty of guaranteeing wired communication and power supply of equipment, and unstable data of vibrating instrument. Consisting of low-power acquisition unit, data concentrator and equipment connection platform, the system transmits real-time wireless data with low-power operation of the automatic acquisition unit. The system is applied to the automatic monitoring of Danjiangkou Dam. Result manifests that the automatic monitoring result does not differ from artificial observation result in terms of accuracy and integrity obviously, and moreover, the frequency and timeliness of the monitored data are higher than those of the observed data. In conclusion, the proposed system solves the problem of safety monitoring automation for slopes and earth-rock dams in construction period, and has good application value and promotion prospect.