After studying the deficiency in C⁴ISR architecture development and research in the field, this paper puts forth the idea of C⁴ISR architecture engineering, i.e. applying the concepts, principles, techniques and methods of engineering to the development and maintenance of C⁴ISR architecture within cost and time constraints. We present the definition of C⁴ISR architecture engineering, and delineate the architecture life-cycle of C⁴ISR system.