Abstract: With the advent of the information age, how to use digital information technology to provide effective assistance for the renewal of the ancient city has become one of the more and more important research topics. In view of the problems that the traditional planning and design method has too much workload in the design of large-area texture restoration and renewal of the ancient city, and it is difficult to deal with the complex condition texture and the dynamic aging and maintenance and renewal of buildings, this paper adopts the CityEngine modeling method, uses the syntax characteristics that its CGA rules can be changed in unification, and adopts the way of manual intervention or automatic iteration. The construction rules of traditional folk houses obtained from the analysis of typology theory are translated into the modeling constraint relationship code and applied to the protection and renewal design of Jianchuan ancient city in Yunnan Province, so that it will not only better assist the maintenance renewal design and dynamic repair management of a large number of traditional buildings in Jianchuan ancient City, but also ensure that the generated scheme conforms to the traditional texture and threedimensional style, so as to provide exploration and new ideas for the restoration of the texture of the ancient city.