Abstract: The serrated teeth in the sealing ring have significant effect on the sealing performance of end fitting of unbounded pipeline, but it is practically difficult to establish a fine model to analyze the sealing structure with serrated teeth. In this paper, the sealing ring inside the end fitting of unbonded pipeline used in one certain sea area was taken as an example. The suitable sealing criterion was defined and the sealing model with serrated teeth was established. Then, the range of optimal penetration depth was obtained based on the sensitivity analysis of penetration depth, and the amplification factor corresponding to the range of optimal penetration depth was calculated. It is indicated that this model structurally has a better penetration depth range, in which the maximum contact pressure and effective sealing length ratio of sealing performance are both better. Besides, by means of the simplified model without serrated teeth, combined with the amplification factor, the sealing performance of an actual structure can be predicated approximately. This method provides the guidance for precisely designing the geometry of wedgy sealing ring, as well as the idea for analyzing the structures with large scale span.