The invention relates to a rolling device for preparing a high-toughness high-formability magnesium alloy sheet strip coil and belongs to the field of metal material rolling. The rolling device provided by the invention comprises a rolling machine, an uncoiling machine, a left-right recoiling machine, a front online heating insulating device of the roll machine, a rear online heating insulating device of the roll machine, a straightening machine, a bending rectifying machine, a thickness measuring device, a steering tension roll, a guide roll, a roller heating and lubricating device and the like. In the invention, an online continuous heating device and an advanced PLC (programmable logic control) feedback control system are adopted, and continuous temperature control rolling on the magnesium alloy strip coil is realized. The rolling device provided by the invention has the advantages of uniform heating temperature, high heating efficiency and high temperature control accuracy, and high-quality thin wrought magnesium alloy strip coils are efficiently produced by virtue of a roller preheating insulating system, a technical lubricating system, a strip shape control system and a tension straightening device, thus the geometric quality and structure properties of rolled metal can meet operating requirements.