The government legal counsel system is an important institutional arrangement for the construction of a law-based government. Its function has gradually evolved from “post-event relief” in the early stage to “pre-event prevention, in-event control, post-event remediation” throughout the entire process of risk management and control, playing the role of “gatekeeper” for maintaining the legitimacy of government actions. This paper takes the innovative practice of the government legal service advisor system in Wenzhou City as a sample and, in combination with the general situation across the country, deeply analyzes the practical difficulties existing in the system in terms of functional positioning, subject selection and employment, operation mechanism, guarantee system, etc. It is necessary to start by clarifying the core functional positioning of the “gatekeeper.” The implementation mechanism of the government legal counsel system is systematically optimized through the establishment of a scientific and standardized selection mechanism, the improvement of a coordinated and efficient operation mode, the strengthening of independent and professional performance guarantee, and the improvement of a digitally empowered smart platform, thereby effectively enhancing its effectiveness in serving the construction of a law-based government.