A number of digital cadastral maps that act as the GIS data sources are based on the AutoCAD platform. Different from GIS data, they do not pay much attention to closure property, topological property and other issues. The closure property test of ancestor parcel is an important component of the conversation of CAD data and of Standardization GIS data and that of Vector Data before cadastral data populated the database. In this paper, the ancestor parcel closure property test is conducted from the technological and theoretical base and the reason is investigated why the ancestor parcel is not closed. It also discusses the flow of testing ancestor parcel closure property, and introdnces a new method by using the technology of AutoCAD ActiveX. The second development is made under AutoCAD 2005, and the ancestor parcel test and the human-computer interaction revision are illuminated. And the problem of results output and ancestor data entering under AutoCAD is addressed. The discussion and research on ancestor parcel test has practical significance for GIS data standardization, and can accelerate cadastre information system construction.