Abstract: This paper sorts out the history of marine spatial planning and urban detailed planning, analyzes the requirements on detailed planning in the current territory spatial planning system. This paper also discusses the necessity of marine spatial detailed planning from usage control, land-sea coordination, and planning purposes, elaborates the feasibility of marine spatial detailed planning from legal logic, management logic, and technical logic, and offers three suggestions on marine detailed planning compilation. It concludes that marine detailed planning is of great significance to the management and utilization of marine space resources, and could be prepared for reclamation, nearshore, and key islands areas where intense development activities exist.