大型复杂技术项目的管理者面对着两个重要的系统，即被研制的工程系统和项目所处的组织机构系统（包括项目团队）。系统工程是成功实现工程系统的方法和技术，它综合多种专业技术，通过分析、综合、试验和评价的反复迭代过程，开发出一个整体性能优化的系统。社会组织系统是开放的复杂巨系统。组织机构的整体能力对大型复杂技术项目管理和系统工程方法的效能具有决定性的影响。必须在组织机构管理中强调系统的观点和方法，核心问题是如何发挥人的积极性、形成强大的群体创造力。这正是系统复杂性研究中揭示系统微观因素对宏观规律的影响机制问题。

Large complex technical programs/projects mainly involve the engineering systems to be developed and the organization systems in which the projects are carried out. It has been a common knowledge that systems engineering is an interdisciplinary approach to enable the realization of successful system. Some commonly used definitions of systems engineering are provided by the best known international technical standards, and they all have a common theme. Nowadays, great needs for systems engineering approach are emerging from major engineering projects in China, but there seems to be a confusion of "what systems engineering is" .The organization system is an open complex giant system. The holistic competence of an organization has an important impact on the success of projects. The systems perspective and approach are essential to organization management. The kernel issue is how to encourage people and how to cultivate an organizational creativity and productivity. In complexity study, this is the issue of the recognition of the micro-mechanism of system macro-emergency property. Neither analytical methods nor statistical methods are able to describe social system complexity quantitatively and accurately.