The invention provides a method for improving a saccharum officinarum seed stem breeding yield and harvesting the saccharum officinarum in advance. The method comprises the following steps: step A, selecting one-level seed stems of healthy seed seedlings, and cutting the stems into segments for usage; step B, preparing land, controlling the tilling depth to be 40cm or more, digging planting furrows with a row spacing of 120cm, a furrow depth of 25-30cm, and a furrow bottom width of 20-25cm, wherein the furrow bottom is smooth, and soil is loosened, smashed and fine; step C, sowing the seed stems, allowing buds to face to two sides, and covering the seed stems with smashed soil; step D, performing thick planting reasonably; step E, after seed stem planting and earthing are finished, preparing a weed killer mixed liquid by adopting 600mL of 80% acetochlor emulsifiable concentrate and 750-1125kg of water, and spraying the weed killer mixed liquid to the planting furrows uniformly; step F, before intertillage and hilling, uncovering a membrane, and in an intertillage stage, applying urea topdressing, and performing hilling; and step G, in a tillering last stage, mixing 3g of gibberellin , 300g of calcium nitrate, 200g of potassium nitrate, 60g of boric acid, 35g of a sugarcane borer removing agent, and 200mg of prochloraz, and dissolving the above mixed materials in 600-800mL of water. The method provided by the invention can promote saccharum officinarum growth and development, the saccharum officinarum can be harvested 6-10 days in advance, and the seed breeding efficiency is improved.