To further study the shear capacity of double steel plate shear walls with internal stiffeners connected at two sides， the finite element analysis of 36 double steel plate shear walls with different width-depth ratios and different height thickness ratios， which are internally stiffened with two-side connections， is carried out by using ABAQUS program. The analysis results showed that the use of thick plates or plates with a larger width-depth ratio can make the steel reach a higher average stress. The ratio of peak mean shear stress to yield mean shear stress has no obvious change rule with height-thickness ratio or width-depth ratio. The variation of strain-hardening ratio with height thickness ratio is between 1.17 and 1.21， and the variation with width-depth ratio is between 1.16 and 1.21， with an average value of 1.19. The formula for calculating the yield mean shear stress of double steel plate shear walls with internal stiffeners connected at both sides is given. The theoretical calculation formula derived from the displacement calculation principle of structural mechanics can accurately calculate the initial stiffness and initial equivalent shear modulus of an internally stiffened double steel plate shear wall. In addition， the equivalent cross brace model of double steel plate shear walls with internal stiffeners connected at both sides is established. It is verified that the equivalent cross brace model can accurately simulate the yield mean shear stress and initial stiffness of double steel plate shear walls with internal stiffeners connected at both sides with different width-depth ratios and different height-thickness ratios. It is shown that the design and analysis of double steel plate shear walls with internal stiffeners connected at both sides can be simplified by using the equivalent cross brace model.