Abstract: Based on the theory of elasticity, some differential equations were derived to calculate the interfacial shear force of a steel-concrete-steel sandwich panel which is characterized with high rigidity and bearing capacity and small deformation, considering the effects of the stress increment in prestressed reinforcements and slippage rigidity. Moreover, the formulae were also given to calculate the interfacial shear force under symmetrically concentrated load. The calculated results showed that the maximum interfacial shear force takes place at mid-span and decreases gradually along board length, and its value approximates to zero at the end. The shear force increases with increasing connecting stiffness/external load but decreases with increasing area of the panel. The stress increment in prestressed reinforcements affects slightly the interfacial shear force, only about 5%. However, the connector stiffness and external load affect greatly the interfacial shear force.