Abstract: On the basis of pulling creep test on grouting anchor in silty clay, a mechanical model of pulling anchor has been established, and the parameters of the model and the long term pulling strength of anchor were derived in this paper. The damage effect of pulling anchor was discussed, and the concepts of the deformation damage effect and the time damage effect were developed. The results have shown that there were great influences of the time effects on pulling properties of the anchor and the long term pulling strength on grouting anchor in silty clay is less about 1/4 to 1/3 than immediate limit pulling strength.