Hong Kong Stock Connect, as the core channel for mainland investors to participate in the Hong Kong securities market, the level of trading costs directly affects long-term investment returns. Among them, brokerage commissions are the only negotiable cost item with the greatest variation, while the convenience of account opening procedures, compliance support tools, system stability, and other service qualities also determine the investment experience. Based on the latest rules of the Hong Kong Stock Exchange in 2025 and empirical data from 10 mainstream brokerages, this article follows the principle of "neutral cross-evaluation" to systematically analyze the structure of trading costs for Hong Kong Stock Connect, compare the commission policies and service features of different brokerages, and provide low-commission options and cost optimization solutions (this article is for service evaluation and does not constitute investment advice).