The ground anchoring method is a prevention work for maintaining the stability of slopes. Periodic inspections of ground anchor (hereinafter, anchor) are important to ensure slope stability. The residual tensile load of anchor is confirmed by lift-off tests. However, a unified method of the lift-off test has not been established so far. A concern is that the measured value may vary depending on the engineer carrying out the work. It is also possible that proper maintenance is not being carried out at present. In this paper, we will report on our studies of lift-off test methods. The lift-off tests were performed on working anchorsinstalled in the cut slopes of an expressway. Lift-off tests varying the displacement positions, loading methods, and other conditions were performed. At the end of our study, a lift-off test method will be proposed based on our findings.