Considering the special requirements of group enterprise information management software, a new method of massive software development was put forward basing on the component technology and facing the "assemblage". It generalizes five key parts of the method system including the overall strategy, the application project method basing on the operation "assemblage", the field project method basing on component, the development method facing the component on the basis of the visible component platform, and the software development process model basing on the component "assemblage". Besides, this paper describes the process and principle of this method application with an example of the construction of a Communications Investment Group enterprise's management information system. The method provides a new idea for breaking away from the predicament appeared in the construction of present enterprise informatization and exploring the way of software industrialization.