In this paper, Macau Taipa Village, a historical district in an island-type city, is the research focus, and a parametric design-based method for designing historical districts is proposed. First, the shape and distribution of roads in historical districts is studied through on-the-spot investigation and measurement and data are collected on the width, depth, and area of street blocks, average street length and width, street orientation, building width, depth, acreage, and height, and building orientation. Second, the acquired data are transmitted to the Grasshopper parameterization platform, and an intelligently generated program produces calculations. Through multiple iterations and evaluations of genetic algorithms based on the needs of modern urban design and planning constraints, the building density is further reduced, and more landscape areas are added. The parametric model is optimized to gradually generate the urban spatial design that meets contemporary requirements. The research reveals that (1) the grasshopper algorithm’s generated block design inherits the characteristics of the conventional historical block. (2) The historical block where the data were collected on site and the block where Grasshopper is applied should maintain the consistency of the regional context. (3) This method can be applied to the design of new urban areas, and the scope of application can be further adjusted through collaboration and the needs of the owners at a later stage.