Lung adenocarcinoma (LUAD) frequently precipitates a hypercoagulable state, resulting in venous thromboembolism and associated hemostatic complications. Furthermore, the coagulation cascade holds a pivotal role within the tumor microenvironment (TME) of LUAD. Utilizing unsupervised clustering of coagulation-related genes (CRG) and integrating clinical attributes, distinctions and correlations in clustering across various groups were assessed. Principal component analysis (PCA) was employed to derive the CRGscore for LUAD patients. Subsequently, a prognostic signature was established to contrast the impacts of immunological and pharmacological treatments across groups. The expression of PIK3CA, posited as a potential biomarker, was corroborated via immunohistochemistry(IHC) and Western blotting. This research delineated pronounced variances in immune signatures and prognostic categorizations among four coagulation-related subtypes, and delved into their associations with three gene cluster subtypes. A prognostic model based on coagulation-related scores was formulated for risk stratification and prognosis estimation. Disparities in immune infiltration, treatment modalities, and drug responsiveness among risk cohorts were discerned. Notably, an augmented expression of the coagulation-associated gene PIK3CA was observed in tumor samples. Coagulatory function is intimately linked with LUAD and its immune microenvironment, offering predictive potential for LUAD survival prognosis. Specifically, subgroups manifesting elevated PIK3CA expression might serve as foundational indicators for optimal treatment selection.