With the increasement of economic strength and significant improvement in science and technology, bridge engineering is developing rapidly towards larger span, deeper foundation and higher tower. Many new problems appears to bridge builders, such as: accurate positioning of deep water foundation during floating and sinking, anti-erosion of super-large caisson foundation, large diameter drilled pier construction, optimization of anchoring structure in long-span cable-stayed bridge tower, temperature control of hydration heat for mass concrete of ultrahigh bridge tower, development of new hydraulic climbing template system for ultrahigh bridge tower. These are the key problems for safe and smooth construction and long-term reliable operation for deep-water long-span bridges. The development and achievements gained in 2020 related to those key problems are analyzed and summarized to improve the construction technology, the problem-solving capacity of the builders and to give technical support for the promotion of deep-water long-span bridges.