The invention relates to a coaxial bidirectional stirring device used in a continuous offshore fracturing fluid blending device. The coaxial bidirectional stirring device is characterized by comprising a stirring tank and a plurality of stirrers, wherein the stirrers are uniformly and fixedly arranged at intervals around the central shaft of the stirring tank; each stirrer comprises an upper motor, a lower motor, an upper transmission shaft, a lower transmission shaft, an upper stirring blade, a lower stirring blade and a coupler; the upper motors and the lower motors are respectively and fixedly arranged on an upper cover plate and a lower cover plate of the stirring tank; the upper ends of the upper transmission shafts and the lower ends of the lower transmission shafts are respectively and fixedly connected with the power output ends of the upper motors and the lower motors; the lower ends of the upper transmission shafts and the upper ends of the lower transmission shafts are connected through the couplers; the upper stirring blades and the lower stirring blades are respectively fixed on the upper transmission shafts and the lower transmission shafts. When a fracturing fluid is blended, the upper transmission shafts and the lower transmission shafts respectively drive the upper stirring blades and the lower stirring blades to make bidirectional rotation along the axes of the couplers under the driving of the upper motors and the lower motors, so as to share and blend the fracturing fluid. The coaxial bidirectional stirring device can be applied to the stirring process of liquids such as the fractural fluid.