Abstract: It is always a difficult and hot issue to study the critical-sliding warning. In this paper,we use the mechanical monitoring method(Newton force monitoring) to monitor the slope of a mountain side highway in Baoxing County,Ya'an. The slope is located at the lower edge of the old landslide of Tangbao landslide. After 4 months of continuous monitoring,we obtain a large number of monitoring data,and two local landslides are successfully predicted during the monitoring period. We first integrate the Newton force monitoring data and rainfall monitoring data,and then compare the monitoring curve with the landslide evolution process,reveal the mechanical evolution law in the process of landslide,and analyze the causes of landslide induced by rainfall. Then,we fit the relationship between the critical-sliding warning time and the landslide volume of the successful cases,and find that there is an obvious positive correlation. Finally,we discuss the relationship between Newton force monitoring method and Saito model,and put forward the idea of monitoring and critical-sliding warning from surface to point. According to the analysis,the Newton force monitoring curve can well correspond with the landslide evolution process. The soil landslide can be divided into three stages: a)the rising stage of Newton force; b) the drop stage of Newton force; c) landslide stage. This paper provides practical experience for the popularization of Newton force monitoring system,and provides a new idea for the research of the combination of mechanical monitoring and displacement monitoring.