With the spectrum extended in modem Electronic War, Laser Countermeasure Weapon will be re-quested in order to snatch up and keep the Electromagnetism-Power in war field. If Command, Control, Com-munications and Intelligence called Double-Army-Power-Implement is applied to general design of Laser Coun-termeasure Weapon System, the efficiency of Weapon System can be greatly improved. The Object-Oriented a-nalysis and design approach based on UML for C3I system architecture was put forward, by which logical archi-tecture described by class diagrams and behavior diagrams can be developed through Object-Oriented analysis,and physical architecture described by component diagrams and deployment diagrams can be developed through Object-Oriented design. The framework of Modeling based UML was firstly set forth, the high process of Com-mand, Control, Intelligence, Surveillance, Reconnaissance and UML Architecture was utilized., Then the Modeling process was particularly discussed through following the core ideology and basic principle of RUP(Rational Unified Process). Next, a series of diagrams of UML diagram which include Activity diagrams, Use Case diagrams, Sequence diagrams, Package diagrams and Class diagrams of system analysis, Component dia-grams, and Deployment diagrams of system design are illustrated in the process of Modeling of C3I system soft-ware. Lastly, some problems that should be noticed in the Modeling process, merit and demerit of model, next works were also put forward.