Abstract: The containment is the key facility to ensure safety of a nuclear power plant，prestressed tendon construction process is an important link for establishing structure system，it was of great significance to study the establishing process． This article was set in a nuclear power plant containment，a large general finite element software ANSYS was selected and a high-quality finite element model was set up quickly with partitioning method，the constraint equations were not set up along the prestressed tendon direction，so that the unbonded prestressed tendon stress state could be simulated truly during prestressed tendon construction; it was put forward multi-cooling-method for simulating the prestress loss caused by concrete elastic deformation，analyzed the concrete stress state，containment deformation and prestressed tendon stress state，hence it was confirmed that the prestress built up in containment was close to the designed prestress，which provided a reliable technical support for containment construction optimization．