At present, the cadastral field, with the conversion into digital cadastral map management system, not the existing cadastral map management system, has gone through a lot of changes, such as the market opening of cadastral surveying and overseas launching of a cadastral field. Such an environmental change has brought on a lot of advantages, such as improvement in accuracy of surveying, efficient management system, and reinforcement of competitive power in cadastral surveying. However, the conversion into the advanced cadastral management system serves to relatively heightening the possibility of outflow of cadastral information and its technology in comparison with in the past. This research, with the aim to cope with indiscriminate outflow of cadastral technology, is aimed at suggesting the plan for the prevention of outflow of cadastral technique and its protection after examining and considering the contents of environmental changes in the currently going cadastral field.