The effect of the loading path on the failure behaviour of slopes was investigated based on the centrifuge model test observations under the application of two typical loading paths: self-weight loading by increasing the centrifugal acceleration and excavation at a constant centrifugal acceleration. Compared with the self-weight loading condition, the slope was more likely to fail under excavation condition, with a significantly deeper slip surface. The quantification results showed that the sequences of slip surface formation associated with the two types of loading path proceeded in opposite directions. A reasonable stability analysis method of slopes should consider the progressive failure and the effect of loading path.