This paper discusses components and architecture framework of C4I simulation system under distributed simulation environment. Combined with a typical example of distributed simulation system, two schemes of C4I simulation system are brought forward, which are based on different architecture: HLA and user-defined LAN communication protocol. Their characteristics are analyzed and their advantages and disadvantages are also compared. Some key technologies such as developing Federation Object Model (FOM) of complex distributed simulation system, information fusion, real-time transmission of communication and intelligence message and C4I oriented synthetic display of multi-dimensional Information etc. are discussed.