It’s difficult to dismantle the reducer and bearings,when maintaining the roller press.So a new structure related to a link construction between the output shaft of the reducer and the axis was designed to replace them quickly.The construction mainly used end face key connection and bolt connection to transfer the torque and bending moment.However when caculating the stress of the structure by hand,it’s difficult to allot the proportion load between the key and bolts.Ansys software was used to analyze the stress of the structure.The quick replacing structure was modeled,meshed,constrained and loaded.Different detailed structure and bolt preload was considered.The analysis result shows that the preload affects composite structure stress the most.Structural change has a certain effect on the composite structure stress.The materials of bolts and key have great influence on the bearing capacity of composite structure.For RP140-65 roller press,the optimum parameters are selected.The preload should be set to 200 kN～ 250 kN.Non-through keyway composite structure makes the key stress lower.Key material should be selected higher performance than 45 steel.Bolts performance class should bet 12.9.After the drawings was designed,the structure was manufactured and put into operation.It’s proved that the structure design is reliable after it has run for five years.This design method can be popularized and applied in the design of roller press.