Bridge steel structure surface treatment auxiliary device

The invention discloses a bridge steel structure surface treatment auxiliary device, and relates to the technical field of bridge material treatment, the bridge steel structure surface treatment auxiliary device comprises a bottom plate, supporting frames and a steel part, the supporting frames are symmetrically and fixedly connected to the bottom plate along the central axis, and the steel part is slidably connected to the bottom plate; the bridge steel structure surface treatment auxiliary device comprises a sand blasting sand grain self-switching assembly and a surface self-adaption treatment assembly, and on the basis that surface sand blasting treatment can be conducted on a steel part through the arrangement of the sand blasting sand grain self-switching assembly, sand blasting treatment different from the middle of the steel part is conducted on the two ends of the steel part; therefore, the surfaces of the obtained steel part after sand blasting treatment at the two ends are rougher than the middle pa