In article 335 of Criminal Law of the People’s Republic of China regarding the crime of medical accidents，the interpretation of“serious dereliction of duty”plays a key role in the determination of criminal liability for medical negligence. However，issues such as insufficient normative guidance and vague judicial determination have led to frequent occurrences of inconsistent judgments in similar cases. Among existing theories， the “subjective theory”“objective theory” and “comprehensive theory” all have deficiencies. Accordingly，we should re-examine the interpretive logic of“serious dereliction of duty”and construct a new comprehensive theory by adopting“gross negligence”as the interpretive framework. Under this theoretical framework，“serious dereliction of duty”is defined as a composite subjective-objective element，requiring simultaneous satisfaction of the standards of“ease and inadequacy in fulfilling the duty of foresight”and“high degree of foreseeability”. The new comprehensive theory not only provides doctrinal guidance for the normative application of the crime of medical malpractice crimes but also，its practical value in clarifying the scope of criminal negligence through case-based analysis.