Focused on the current issues of scattered, multi-source and isomeric knowledge in the field of public health, the international and standardized semantic mapping mechanism of terminology was discussed to support knowledge aggregation and emergency decision-making. Taking the infectious disease knowledge organization system CIDO, IDO, and GenEpio in the public health field as examples, this paper presents the central structure model from ISO 25964 as the semantic mapping model of terminology. Combined the method of semantic similarity and text similarity calculation, the semantic similarity between terminologies based on inheritance reasoning was computed. The experiment indicated that the increased hierarchical relationships amount to 72 terms(13.43%), which not only improved the connectivity among multi knowledge systems, but also optimized the standard process of term mapping. It is an effective mechanism to public health knowledge construction and sharing in emergency management decision-making.