Advanced military and large scale commercial systems are getting bigger and more complex as we approach the 21st century. A new systems engineering paradigm which employ simulation and modeling capabilities may provide significant opportunities to reduce cost, schedule and risk in the development of large complex systems. The central feature of a simulation based systems engineering paradigm is an advanced systems engineering environment which supports synthesis, capture, analysis, simulation and optimization of complex system designs.The focus of this paper is a description of a high level architecture for such an environment. The essential components of an Advanced Distributed Complex Systems Engineering (ADCSE) environment are partitioned into five categories: (1) A generic computing infrastructure; (2) ADCSE specific schema; (3) the capability to support execution of distributed simulations; (4) application specific tools; and (5) Design libraries of reusable components.