In order to evaluate the suitability of site selection for marine ranching in the northern sea area of Weifang city in Shandong province, support sustainable utilization of marine resources and highquality development of marine economy in this region, based on the investigation work carried out by Shandong Geological Exploration Project, singlebeam surveying, sediment and seawater sampling in the northern sea area of Weifang city have been carried out. By integrating multidimensional data, such as marine environment, engineering geology and social and economic factors, a multicriteria evaluation system for the suitability of marine ranching site selection has been innovatively constructed by using "Analytic Hierarchy Process (AHP) + Decision Judgment". It is indicated that the northern sea area of Weifang city is suitable for the construction of three types of marine ranches, they are bottomsowing type, reefcasting type and pastoral type. The suitable areas for bottomsowing marine ranches are mainly distributed in the southern and northern parts with a cumulative area of 634.77 km2, accounting for 58.79% of the total area. The suitable areas for reefcasting marine ranches are primarily located in the southern part with a cumulative area of 294.60km2, accounting for 27.29% of the total area. The suitable areas for pastoral marine ranches are mainly distributed in the southern and northern parts with a cumulative area of 534.75 km2, accounting for 49.53% of the total area. The study area has significant potential for the construction of marine ranches, but site selection needs to comprehensively consider engineering geology, shipping channels, ecological red lines and marine special protection zones. This study will provide critical references for regional marine ranching construction planning, fill the gap in comprehensive evaluation of multitype marine ranching site selection in this area, and hold significant importance for promoting the sustainable development of marine fisheries.