Abstract: Based on the principle of equivalent strain, the effect model of anchorage force loss in weakly consolidated soft rock is established by the combination form of “Maxwell + Kelvin”, considering the coupling effect of supporting anchor cable and pre-reinforced soft rock. Taking a case of anchorage cable reinforcement as the background, the applicability and effectiveness of the model are discussed, based on the methods of theoretical calculation comparing with field measured data. Results show that the model can reasonably reflect the anchorage force loss caused by soft rock creep, and the deformation curve is close to the measured values. Relationship between the change of anchoring force and deformation of surrounding rock is realized by calculation, and the development process of the deterioration of surrounding rock and supporting body is explained.