Authenticity is an essential component of test validity and usefulness, and its importance role in language for specific purpose (LSP) test is more prominent since LSP test is practical and assesses test takers’ language ability in real-world situation. But how to assure the appropriate authenticity is still unclear and rare studies have ever examined the authenticity in the current LSP test. Herein, this study attempted at exploring the health professionals’ perception of authenticity in a LSP test Medical English Test System (METS) in China context using questionnaires and interview. The results demonstrated that a majority of participants admitted the importance of speaking task and the METS. Though the needs for English literacy activities are relatively low, preparing for the METS is still considered meaningful and beneficial. Compared with medical students, health professionals hold a more positive attitude towards situational authenticity and rated higher authenticity in the METS test. With sufficient clinical experience, the health professionals stressed the positive impact of METS on English learning and clinical communication. In conclusion, the situational, interactive and textual authenticity of the METS is recognized by the health professionals and medical students but still needs improvement. The METS fails to appropriately meet the demand of health professionals in the healthcare sector in the China context.