For the main steam pipeline arrangement in nuclear power plants, this paper analyzes the loading characteristics of the vertical pipe rigid supports under different installation forms, and uses the finite element method to calculate and analyze the influence of the angular movement restraint effect of the vertical pipe rigid sup-ports on the stress of the main steam pipeline and the loading on the supports. The analysis reveals that vertical pipe rigid supports with varying structural designs exhibit distinct effects in restraining angular movement. In case of improper design and selection of supports, the displacement stress of the main steam pipe-line will exceed the allowable value, and the actual loads of the pipeline rigid supports and the limit devices will exceed the designed values, resulting in the deformation and damage of the pipeline supports. The calculation results indicate that the design of rigid supports for pipe nodes with significant angular displacement in low flexibility pipelines should carefully consider both the structural configuration and installation orientation.