Abstract: By the use of the method of numerical simulation,reinforced effects on rockmass of free pre-stressed cable are researched by changing pallet dimension and applying different ways of pretension force.The results of research indicate that under different pretension two compression stress concentration zones come into being in rockmess near pallet and anchorage and stress intensity lies on pretension force and pallet dimension.The smaller pallet dimension is and the higher pretension force is,the higher axial stress intensity is.Axial stress of cable is average in free session and dies down in anchorage.As to the loss of pretension force,there is a close relationship between the degree of the loss of pretension force and pallet dimension.The bigger pallet dimension is,the less the loss of pretension force is.While pretension force make a little difference to the loss of pretension force.A reference can be provided for the engineering design and theoretical study.