Abstract: Modular steel building is a new type of prefabricated building structure system. It has become the development trend of building industrialization and has been gradually valued and widely applied in China， because of its advantages of rapid assembly on site and recyclable materials. The inter-module joint has a significant impact on structure performance， and therefore the joint which can take both convenient construction and reliable force transmission into account is one of the key technical difficulties in the widespread application of modular steel buildings. In this study， the research focused on the connection joint between module units of modular steel buildings and especially conducted an in-depth research on the design and analysis of a new type of joint which is adaptable to construction errors， considering the actual situation of construction errors during site construction. By using wedge-shaped blocks in the joint， the new joint can be moderately adjusted in the construction process to ensure the construction convenience and efficiency， while taking into account the mechanical properties of the joint such as tensile properties， compressive bearing capacity and shear resistance. The basic mechanical principles of introducing wedge-shaped blocks to adjust construction errors， the detailed design scheme，calculation method and on-site installation process of the new type of joint were expounded. The advantages and disadvantages of the joint were also analyzed， and another structural form of the joint was given. The new type of joint has the advantages of simple structure， clear force transmission， convenient on-site installation， adaptable to certain construction errors， and can meet the requirements of mechanical bearing capacity， which can be widely used in modular steel buildings.