Article 16 and Article 17 of the Supreme People’s Court’s “Pilot Implementation Measures for the Reform of the Streaming of Civil Proceedings in a Complex and Simple Manner” initially stipulate the “expansion of the scope of application of the sole-client system” in the trial of ordinary procedural cases in the basic courts，i.e.，“where the facts are not easily ascertainable but the application of the law is clear”. “In addition，there are also nine circumstances that preclude the application of the single-judge system，but there are no detailed guidelines on the scope of cases in which”“the facts are not easily ascertainable，but the application of the law is clear”. In view of the large volume of the first instance ordinary procedure cases in the basic courts，this paper takes the realistic dilemma of “expanding the scope of application of the sole proprietorship system” as a presupposition，explores the root of the dilemma，explores the boundary of understanding the direction of expanding the scope of application of the sole proprietorship system from the perspectives of the purpose of litigation，the value of the system and the litigation rights of the parties，and explores，on the basis of theoretical support. The first instance ordinary procedure cases in the grassroots courts to determine the boundaries of the scope of application of the exclusive system，in order to deepen the reform of the application of the first instance ordinary procedure exclusive system is helpful.