Abstract: Form finding analysis of cable domes is one of the key engineering problems. However, the rigid displacement which is comprised in the process makes the analysis more complex. In this paper, a method based on modified dynamic relaxation is presented, and the problem of rigid displacement is therefore effectively solved. The method includes two steps: first, releasing the stretched cables, second, imposing the axial force at two ends of each released cable instead. This method is convenient for calculation and clear in conception. Case study and model experiment indicate that it is applicable to the simulation of construction process of various cable domes and cable-strut tension structures.