In order to study the simplified calculation methods of interlayer stresses for Super Toughness Concrete (STC) composite bridge deck pavement, finite element analysis was carried out by ANSYS software. The influence laws of steel -STC-SMA structure thickness, ambient temperature, and longitudinal slope on interlayer stress were discussed. The stress estimation models for STC composite bridge deck pavement were established. The simplified calculation formula of maximum shear stress and maximum normal tensile stress between layers were presented. The results show that the interlayer stresses are influenced by some factors such as the thickness of SMA and STC, environmental temperature, and longitudinal slope. Under the most unfavorable load combination, the maximum interlayer shear stress variation range is 0.38~0.55?MPa (normal temperature) or 0.35~0.55?MPa (high temperature), and the maximum normal tensile stress ranges from 0.18 to 0.23 MPa，when the deck longitudinal slope is not taken into account. The interlayer stress increases linearly with the increase of the longitudinal slope of the bridge deck. If the longitudinal slope increases from 0 % to 8%, the maximum layer shear stress is increased by 9.4% (normal temperature) or 12.0% (high temperature), and tensile stress by 12.0% (normal temperature) or 12.5% ??(high temperature). The general calculation formula of stress between deck pavement layers of the STC composite bridge is established by modifying the longitudinal slope degree. Compared with the finite element calculations of a real bridge, the error is less than 9%, indicating that the methods proposed in this paper can be used to estimate the interlayer stress of STC composite bridge deck under different longitudinal slopes.