Movable steel rolling online heating device

The invention relates to the field of steelmaking detection, in particular to a movable steel rolling online heating device which comprises a movable supporting structure, a support connecting structure, a burner mounting structure and a burner. At least one side end of the support connecting structure extends outwards in the direction opposite to the supporting structure to form an outer overhanging part, the burner nozzle installation structure is arranged at the outer end, away from the supporting structure, of the outer overhanging part in a suspended mode, and the burner nozzle is arranged on the burner nozzle installation structure. A gap is formed between every two hole patterns on a rolling mill, and a burner nozzle is flexibly and opportunistically inserted into the gap, so that a rolled piece from a previous hole pattern can be directly heated on line. Therefore, the temperature of a rolled piece can be compensated online, steel with poor hot working performance does not need to be heated in a rolli