Natural, technical and man-made disasters pose enormous threats to the safety and stability of cities. Urban resilience focuses on the ability of cities to resist, recover from and adapt to disasters. Meanwhile, the urban system and its subsystems are highly complex and interdependent, therefore they can be viewed as a system of systems in the trio-spaces of physical, societal and cyber spaces. Only by optimal allocation of resources among different sub-systems of the city and different phases of its resilience capacity building can urban resilience be ensured and enhanced in the most effective manner. The team at Tsinghua University has been studying urban resilience from a trio-space perspective, investigating infrastructure resilience, healthcare system resilience, economic system resilience and community resilience. The outcomes can provide new insights into the improvement urban resilience.