In light of the problems of that the highway rock slopes have large numbers and slope stability is hardly to predict in time

the stress monitoring method of the anchoring rock bolt is used to evaluate slope stability. Typical slope along Guangyuan- Shaanchuan expressway reconstruction as the example

the FLAC3D software is taken to simulate the excavating and support process of the rock slope

and the strength reduction method is taken to analyze the change of rock bolt axial force during the rock mass strength reduction process

the monitoring values are obtained; and combined with the result of field test to evaluate the slope stability. The research results show that the mainly monitoring locations should be at mudstone structures

and the stress monitoring is a wholly system; so that the early warning should be made if axial force values at any locations reached the early warning values; The result of field test shows that the stress monitoring has obvious change at 120 d

while the displacement change has a time lag

it appear obvious change at 167 d; from the results of stress monitoring and displacement monitoring

a conclusion is drawn that the slope keep in a state of safety operation

so the proposed stress monitoring method can be applied to evaluate the highway rock slope stability.