Modelling and simulation are important means for top-level design, concept demonstration, design analysis and optimization, and capability assessment of large-scale complex systems. With the acceleration of the construction of the equipment system development, the system fusion degree and system contribution rate of weapon equipment has become the focus problem. In view of the difficulty in assessing the system fusion degree and system contribution rate of weapon equipment, the concept of simulation as a service (SaaS) is introduced into the LVC system test, and three aspects of research are carried out. Firstly, this paper explaines the basic concept of the system test and SaaS, puts forward the basic method of system test, and the technical requirements of the system test based on SaaS. Secondly, the basic construction of SaaS based LVC simulation method is proposed, and the key technologies are analyzed. Finally, this paper puts forward three kinds of the system test organizational model and the test equipment system construction method, and analyzes the flow of the LVC system test based on SaaS.