In the study of Chinese neologisms, the description of word formation is too much, and the explanation of metaphor generation mechanism and cultural cognition is insufficient. This paper proposes a computational framework for word formation analysis of Chinese neologisms. Based on 12,480 self-built corpora, this study constructs a joint model of metaphor mapping and cultural cognition of neologisms, focusing on word formation component identification, metaphor mapping extraction, cultural prototype modeling and relevance attention mechanism optimization. This method integrates character-level boundary recognition, contextual semantic representation and cultural prototype memory into a unified process, which can simultaneously depict the source-target correspondence and its socio-cultural orientation. The experimental results show that the Macro-F1 of the proposed model on the metaphor mapping recognition task reaches 0.913, and the Accuracy is 0.924. The Macro-F1 and Accuracy on the cultural cognitive classification task reach 0.879 and 0.891, respectively, which are better than rule matching, SVM+TF-IDF and Chinese BERT baselines. The research shows that the meaning generation of Chinese new words is not a simple lexical splicing, but a compressed cognitive construction process under the joint effect of metaphor mapping and cultural experience.