Abstract: For the anchoring flange, the size of each part calculated by the conventional calculation method is more conservative, structural size ofimportant parts is often unreasonable, local stress is too large and necessary analysis and optimization are quite insufficient. Take one highpressure and heavy diameter anchoring flange as an example, the theoretical calculation and finite element analysis method are integrated for analysis and calculation. Results show that the maximum stress intensity is distributed at the flange fillet and pipe neck, stress components in the other positions are smaller, strength check meets the requirements and structural design is reasonable. Therefore, the anchoring flange design calculations combined with the finite element analysis can ensure design quality, to meet the anchoring requirements of different projects.