Abstract: In recent years, modular steel structures have gradually burgeoned an important development direction for construction industrialization in China, owing to their advantages in construction efficiency, environmental protection and etc. The inter-module connections have an important influence on the mechanical behavior of modular steel structures. Scarce research has been conducted on inter-storey shear performance of the inter-module connection. An innovative fully prefabricated liftable connection (FPLC) for modular steel structures was thusly proposed and the shear performance as well as calculation method on shear capacity of the FPLC were studied systemically. Shear performance tests were carried out on eight full-scale specimens to investigate the failure mode, force transmission mechanism and ultimate load bearing capacity of the FPLC under inter-storey shear force, and to discuss the effect of the strength and number of the long stay bolts on shear performance of the FPLC. A refined finite element model on shear performance of the FPLC was established, and validated through the comparison with the experimental results. The development of the internal force of the long stay bolts was analyzed and the failure mechanism of the FPLC under shear force was revealed. The effect of key parameters such as diameter of the vertical bolt, thickness of the inner plate and diameter of the long stay bolt on shear performance of the FPLC were analyzed by the finite element model established. A theoretical calculation model for the FPLC under inter-storey shear force was established, and the correctness of the derived theoretical equations was verified by comparing the theoretical results with the experimental and numerical ones.