根据《中华人民共和国行政诉讼法》(下简称“行诉法”)之规定,作为国家法律监督机关的人民检察院“有权对行政诉讼实行法律监督”。对行政诉讼实行法律监督,不仅是宪法原则的体现和法律赋予检察机关的一项重要权能,而且也是保障“行诉法”正确贯彻实施的一项自我保护措施。何为行政诉讼法律监督之“外延”?即检察机关在何时、何阶段、何方面对行政诉讼活动实施法律监督? Pursuant to the provisions of the Administrative Procedure Law of the People’s Republic of China (hereinafter referred to as the “Administrative Litigation Law”), the People’s Procuratorate, the supervisory organ of state law, has the power to exercise legal supervision over administrative litigation. To supervise administrative litigation is not only an embodiment of the constitutional principle and an important empowerment given by the law to the procuratorial organs but also a self-protection measure that guarantees the correct implementation of the Law of Appeal. What is the “extension” of the legal supervision of administrative litigation? That is, when, how and when the procuratorial organs carry out legal supervision over administrative litigation activities?