Finite element method as a very effective numerical analysis method applying in the analysis large-scale complex structure.This article introduced the space non-linear finite element analysis method,the iteration method and increases method which was often used in the analysis non-linear problem and their respective shortcomings were discussed.Mixed method which becomes by iteration method and increase method union,effectively solved shortcomings and insufficiencies of purely iteration method and increase method.Finally,the finite element computation to the engineering structure was carried out by applying the mixed method and its bearing capacity was analyzed.The results showed that the error of analysis space non-linear problem could be reduced.