According to the structural characteristics of the parallel steel wire rope， the slippage development mechanism between the wires can be studied by the frictional variable width laminated beam model． When the inter layer shear force of the coulomb’s frictional laminated beam exceeds the maximum friction resistance between layers， the slippage between layers will occur． In order to accurately study the interlaminar slip mechanism of the frictional variable width laminated beams， the formula for calculating the shear force of the frictional variable width laminated beams considering interlaminar friction is derived by the section analysis method， then determines the interlaminar slippage law of the frictional laminated beams; And then the Transfer Matrix method is used to calculate the slippage length; Finally， the ANSYS numerical simulation results are compared to verify the accuracy of the algorithm．