The UHVDC converter transformer structure is complex, and the valve, grid, and voltage-regulation windings are the crucial components that realize voltage conversion and energy transmission. When short circuit happens in the system, the converter transformer windings need to have the ability to withstand the short-circuit force to avoid serious accidents, so the winding force characteristics and stability are the essential factors to estimate the quality of the transformer. At present, there is a lack of analysis of the winding resistance and force stability of UHV converter transformers. In this paper, the short-circuit force stability of different windings is calculated, and the suggestion for improving the stability of windings are given.