Abstract: Most key functions of complex systems are implemented by software. As a result, software has critical effect on dependability and quality of those systems. But software development and management of current complex systems mainly follow general systems engineering approach which does not consider complex systems’ characteristics like openness, emergence, selforganization, and so on. This limitation increases the risk of dependability and quality. To ensure dependability and quality of software in complex systems, the major characteristics of complex systems are taken into consideration, and some technologies and theories of systems science are adopted to improve the existing software development and management approaches, especially the software analysis and design approach. In addition to systems science, agile method, knowledge engineering and other related technologies are introduced to establish a software life cycle model which covers both technical processes and technical management processes and reflects the multidimensional views including software development、verification and maintenance.

Key words: complex systems, systems science, software life cycle model, agile method, knowledge engineering