The medical assistance system is an important part of the multi-level healthcare security system, and a key institutional mechanism to promote equity and justice. As representatives of four typical medical insurance models, including the Beveridge model, the Bismarck model, the market-based insurance model and the mixed model, six developed countries, namely the United Kingdom, Japan, Germany, the United States, Singapore and Australia, have developed more mature and comprehensive medical assistance systems. This study systematically reviews and compares the current situation of medical assistance systems in these six countries and China to identify the problems that need to be solved and improved in China's medical assistance system. Drawing on international experience, this study puts forward relevant suggestions, including improving the legal and regulatory framework, expanding financing sources, enhancing the function of central top-level design, strengthening the accurate identification of eligible beneficiaries and optimizing the tiered financial burden reduction mechanism that prioritizes insurance before assistance, aiming to promote universal health coverage in China.