In order to improve the problem of preload relaxation and uneven distribution of double-headed studs during the tightening process of ultra-high pressure flange double-headed studs, which ultimately affects the sealing properties of flange connections. An elastic interaction matrix was established through existing literature, and finite element analysis method was used to study the preload distribution of studs under different fastening processes in the fastening sequence, number of fastening shafts, and fastening wheels. Based on this, the advantages, disadvantages, and applicability of different fastening processes were compared and analyzed. Finally, the elastic interaction coefficient method (EICM) was used to optimize the initial pre tightening force of the bolts. The results show that the star mode in the single-axis fastening mode and the four-axis circular mode in the multi-axis fastening mode are the best, and the preloading force of each stud after tightening is closer to the target preloading force. At the same time, fewer load steps are required. Secondly, increasing the fastening wheel can effectively make each stud close to the target preload force after tightening, and the discreteness is smaller. In addition, the initial preload force of the stud optimized based on EICM is adopted after tightening, the final preload distribution of the obtained stud was significantly improved before optimization. It is concluded that the research results can provide theoretical guidance and technical support for the fastening of ultra-high pressure flange double-head studs.