Purpose: Following the Rehabilitation Treatment Specification System (RTSS) framework, the current study investigated the active ingredients in the modified semantic feature analysis (mSFA) targeting either noun or verb retrieval in Mandarin-English bilingual adults with aphasia (BWA). Method: Twelve Mandarin-English BWA completed mSFA treatment for nouns and verbs. Eight of them completed both noun and verb treatment, while four completed either type of treatment. Performance in each step was scored and analyzed using mixed-effects modeling. Then, regression was performed to estimate the effect of treatment performance on the accuracy of naming probes for trained and semantically related items in both treated and untreated languages. Results: Participants demonstrated significant improvements in all treatment steps during both noun and verb treatment, yet the effect varied depending on the trained word category and treatment language. Moreover, all treatment components contributed significantly to the treatment outcomes. Better treatment performance in spontaneous naming was significantly associated with improved naming accuracy of the trained items in noun mSFA, while better treatment performance in spontaneous naming, feature analysis, and sentence production was significantly associated with enhanced naming of the semantically related untrained items in noun mSFA. Importantly, performance in all treatment steps of both noun and verb mSFA significantly predicted naming accuracy in the untreated language. Conclusion: Findings provided strong evidence of the potential active ingredients of semantic-based naming therapy in Mandarin--English BWA and highlighted the importance of examining treatment ingredients within the RTSS framework.