At present，there is little research on the influence of shear deformation on the transverse load distribu-tion of steel-concrete composite box girder bridge． Firstly，on the basis of considering its own shear deformation，the stiffness reduction coefficient was obtained by sinusoidal load． The eccentric pressure method，the modified eccentric pressure method and the rigid connection beam method considering the shear deformation effect were used to deduce the calculation formula that calculates the transverse load distribution coefficient of the composite small box girder bridge of multi beam type corrugated steel webs-steel floor-concrete roof (CSWSB)． Then，a real bridge with multi beam type improved corrugated steel webs composite small box girder was selected for experimen-tal study． Finally，the results calculated by the calculation methods discussed in this paper were compared with the results of the finite element method and the test values． The results show that the deflection value of the rigid connection beam method considering the shear deformation effect is closer to the simulation value of ANSYS，and
the rigid connection beam method considering the shear deformation effect should be used to calculate the transverse load distribution coefficient of the midspan． When the bridge structure does not meet the narrow bridge conditions，the rigid connection beam method considering the shear deformation effect should be used to calculate the transverse load distribution coefficient of the midspan section． When the bridge structure meets the narrow bridge conditions，the modified eccentric pressure method considering the shear deformation effect can be used to calculate the trans-verse distribution coefficient．