The invention provides a high precision mobile device of a welding robot. The high precision mobile device of the welding robot comprises a workpiece platform, a submerged arc welding machine body, avibration slag removal device and an absorption device. A rectangular frame is arranged on the workpiece platform, and clamping devices for clamping workpieces to be welded are oppositely arranged inpairs on four directions on the workpiece platform. The submerged arc welding machine body is slidably connected to the rectangular frame through a tracking parallelogram linkage device, and a weldinggun of a submerged arc welding machine is in contact with weld joints of the workpieces to be welded in sequence. The vibration slag removal device is connected to the rear of the submerged arc welding machine body through a connecting rod device and slips synchronously with the submerged arc welding machine body. The absorption device comprises a soldering flux absorption pipe and a soldering slag absorption pipe. According to the technical scheme, the submerged arc welding machine body moves welding through the tracking parallelogram linkage device, the multi-layer welding is carried out onthe multiple workpieces to be welded circularly, the automatic cleaning the soldering slag and the double recovery of soldering flux are adopted, so that the soldering flux is fully recovered and utilized.