The rolling and bending method of a straight edge coil tube rolled by a three-roll plate rolling machine includes the following steps: the rolling and bending mechanism is used to preform the straight edge coil tube and then roll and bend it. The invention can realize the continuous rolling bending manufacture of a coiled tube with a straight edge through the continuous working steps of preforming, rolling bending and shaping; It is easy to realize the automatic manufacturing of steel pipe, which greatly reduces the production cost, improves the quality and efficiency of the product, and is suitable for mass production.