The invention discloses a rapid doubling method of a tobacco polyploidy. The rapid doubling method comprises the following steps: selecting tobacco seeds with known germination rate and treating the seeds with 0.4 percent colchicine the day before germination; rinsing the treated seeds, directly sowing the seeds on a seed culture medium; screening stocky seedlings and directly planting the stockyseedlings on a floating seedling culture disc; and carrying out ploidy identification after the stocky seedlings grow up. By adopting the method disclosed by the invention, tens of thousands of seedscan be treated in one step; a screening process is simple to operate, seed and seedling disinfection treatment is not needed and a tissue culture system does not need to be established; plant systemswith different ploidies can be obtained through one-time treatment; and the rapid doubling method has the advantages of less drug dosage and simplicity in operation, and the aim of rapidly doubling tobacco chromosome sets in a low-cost and high-throughput manner is completely realized.