The invention relates to the field of air pump production, in particular to a tin soldering device of an air pump tin soldering assembly line. The tin soldering device includes a second supporting column vertically arranged, an electric actuator, a tin soldering assembly and a driving assembly driving the tin soldering assembly to move vertically. The electric actuator is installed at the upper section of the second supporting column. A connecting plate is installed on a sliding block of the electric actuator. The driving assembly is connected with the second supporting column, and the tin soldering assembly is matched with the connecting plate in a sliding mode. The driving assembly includes a first fixed plate, a second fixed plate, a motor and a lead screw. According to the tin soldering device, when an air pump reaches to a working area of the tin soldering device, the connecting plate is driven to move horizontally by the electric actuator, the first connecting plate is driven tomove horizontally by movement of the connecting plate, a regulating block is driven to move by movement of the first connecting plate, a tin soldering pen is driven to move to be over a tin solderingsection by the regulating block through a connecting part, the first connecting block is driven to move down vertically by the rotation of the lead screw driven by the motor, and after tin soldering of the tin soldering pen is conducted at the tin soldering section, the tin soldering pen moves into a loading box on a support frame.