The invention discloses a fertilizing method for flue-cured tobacco in a whole growth period in a high-altitude tobacco-growing area through plastic film mulching and relates to a flue-cured tobacco planting technology. The fertilizing method comprises the steps of completing pretreatment on tobacco-growing land 20-30 days before transplanting, and determining an opening distance according to the soil fertility; taking 70% of a base fertilizer accounting for the total application weight to be applied to two sides of tobacco plant rows for double-strip application, afterwards ridging, then determining a nest distance according to the soil fertility, using the residual base fertilizer as a root anchoring fertilizer, uniformly and circularly spreading over planting positions of tobacco plants, timely mulching plastic films according to the soil moisture content, then punching at the centers of the positions of the root anchoring fertilizer by utilizing a transplanting puncher, drenching root anchoring water to ensure the survival of tobacco seedlings, afterwards transplanting the tobacco seedlings, beginning to check the seedlings and filling gaps with seedlings 5-7 days after the transplanting, then carrying out intertillage, uncovering the films and earthing up, topdressing and irrigating, topping and removing branches in an optimum period, and timely carrying out diseases and insect pest prevention and treatment. According to the fertilizing method, the root anchoring fertilizer is applied in advance, so that the survival rate of the tobacco seedlings and the flue-cured tobacco quality can be improved, the labor cost can be greatly reduced, and the fertilizing method has obvious economic benefits.