Butterfly valve assembling device

A butterfly valve assembling device comprises a machine base and two positioning dies, the machine base is provided with a positioning plate, the positioning plate is provided with positioning columns, each positioning die comprises a support and two positioning blocks, a positioning groove for positioning a valve plate is formed between the two positioning blocks, the lower positioning die is installed on the positioning plate, the support is clamped among the multiple positioning columns, and the positioning columns are clamped between the two positioning blocks. The upper positioning die is connected with an up-down air cylinder, the valve body is positioned on the support through a positioning column, the valve plate is positioned through a positioning groove, and the valve plate is pressed downwards and positioned in the valve body through the up-down air cylinder and the upper positioning die. A piston rod of the push rod air cylinder extends towards the lower positioning die, the piston rod end of the