With the transformation of the computing power supply pattern in the digital economy era, the new network infrastructure with computing power as the core has become an important driving force to realize the sharing of computing power resources and support the digital economy transformation. In the computing power network, multiple heterogeneous user terminals access the network frequently in various ways to obtain computing power services anytime and anywhere, which increases the openness and dynamics of the network. Hence, the computing power network will face more severe security challenges. However, the traditional network-based security defense pattern usually statically supplements security protection components for specific security issues, which cannot actively adapt to user needs to adjust defense strategies flexibly, which is difficult to deal with security risks in computing-network integration scenarios. Therefore, facing the security requirements of the new computing power network, this paper regards security as the internal attribute of the network and proposes a multi-dimensional collaborative autonomous defense paradigm based on the smart computing integration networks, which combines the design of “three layers” and “three domains” of the network. In the “three layers”, this paper defines the security inherent service at the generalized service layer, adapts the security function at the mapping adaptation layer, and executes the security strategy at the fusion component layer. In the “three domains”, the resource adaptation is guided by the entity domain, the security service process is driven by the knowledge domain, and the specific security technologies are implemented by the sense control domain. It constructs a basic management and control process that integrates “detection”, “trace”, and “defense”, in which security policies and technologies can be flexibly adjusted according to scenario scalability and business security. Finally, the proposed paradigm is verified through simulation experiments, and the results prove the effectiveness of the proposed paradigm and also provide a reference for further research and application of smart computing fusion security in the future.