As a political communication medium, the 12345 government service hotline is deeply embedded in China’s bureaucratic political system. With the development of information technology, in practice, it has begun to change from a single telephone medium to a new platform for all-media livelihood services. Based on the perspective of political process, the research conducted an in-depth analysis of the dynamic mechanism of the operation of the 12345 mayor’s hotline media, and the reconstruction of the government-citizen communication system in the grassroots governance and the shaping of responsive government image from the two dimensions of interaction within the bureaucratic government system and interaction between government and citizens. The study found that, in response to the inertia of grassroots governance in the new era, the municipal government used the 12345 mayor hotline as a platform to reinvent the administrative process, involve the masses in administrative assessment and force the institutionalized response to the “rule of law” affairs. The three major mechanisms of democratization have reshaped the power and responsibility system of city grassroots governance, and improved government responsiveness. However, the efficient operation of the 12345 hotline platform faces the problem of “responsiveness paradox” in practice. Grassroots governance needs to find a governance balance between supervising grassroots governance inertia and filtering unreasonable demands.