The frame prestressed anchor cable computational model for system reliability is put forward basing on a series system

which is constituted with main failure modes of the frame beam destruction in tension stage or in working stage

destruction of stringers and beams

destruction of the beam in cross-section and oblique section

and anchor damage. During tensioning stage

the anchor cable force is assigned on the beams in accordance with the principles of displacement coordination and static balance; internal forces of the monolithic beam is calculated respectively by Winkler elastic foundation beam model. In the working stage

to calculate their internal forces

the lateral earth pressure coefficient is regarded as random variables

frame beams as simply supported beam under the earth pressure. Basing on the correlation coefficient matrix of the failure mode function

prestressed anchor computational model for reliability of the system and computer program are then derived. The results of an engineering example show that the probability of failure of the prestressed anchor frame is determined by three factors: cross-section failure probability of in working stage

cross-section failure probability of tensioned stage and anchor bolt failure probability. Assuming the error of three failure modes interdependent system failure probability and system failure probability considering correlation is 8.1%.