Abstract: Pre-stressed High-strength Concrete(PHC)piles, as a common method for treating wet and soft loess foundations, have stable and reliable quality. However, in the traditional PHC pipe pile construction process, the recording of the pipe pile penetration displacement has problems such as insufficient frequency and low efficiency, which fail to meet the expected monitoring effect of foundation treatment construction. In view of this, based on the basic framework and technology of the Internet of Things, relying on Gansu Anlin Expressway PHC piles to treat wet and soft loess foundations, a set of PHC pile construction quality automatic monitoring systems are designed, and self-developed monitoring devices are used for piles. During the construction process, the quality control index of the penetration displacement was monitored and tested on-site. The results show that the monitoring system can output the response of the penetration displacement of the piles into the soil layer with the number of hammer strokes in real time and feed back the information of the piles penetrating the bearing layer to the on-site construction work area in time. At the same time, the reliability of the monitoring system was verified with the help of geological radar and low-strain detection technology. The research results can provide certain technical support for the intelligent collection of penetration information of PHC piles during the construction process.