A full-range high-precision air volume adjustment device, comprising a ventilation pipeline (1), wherein two air volume adjustment valves are installed between inner walls of the ventilation pipeline (1), and the two air volume adjustment valves are respectively a fine air volume adjustment valve and a coarse air volume adjustment valve. In the adjustment process for a stable air volume, the opening degree of the fine air volume adjustment valve is decreased as the opening degree of the coarse air volume adjustment valve is increased, and the opening degree of the fine air volume adjustment valve is increased as the opening degree of the coarse air volume adjustment valve is decreased. Coarse adjustment and fine adjustment are combined for adjustment, so that the problems in the existing ventilation industry of the overall accuracy of air volume adjustment being poor, the adaptability of adjustment within different air volume ranges being poor, and accuracy being unable to be stabilized within an adjustment range, can be effectively solved.