The invention relates to the preparation technology of boron-containing glass tubes, in particular to a preparation method of an ultra-long high-precision boron-containing glass tube. The preparationmethod comprises the following steps: proportioning the following raw materials in parts by weight: 3-5 parts of sodium oxide, 0-2 parts of potassium oxide, 12.5-12.9 parts of boric oxide, 1.5-3 partsof aluminium oxide, and 81.1-85.5 parts of silicon dioxide, uniformly mixing the raw materials through a ball mill at the rotation speed of 5-20 revolutions per minute to prepare a batch; melting thebatch in an electric melting furnace to obtain glass metal, and discharging into a material basin; enabling the glass metal to flow out through a material bowl at the bottom, blowing the glass metalinto a tube shape by compressed air introduced from an air supply pipe in the center of the material basin, and downwards drawing the glass metal to form the glass tube by a tractor, enabling the drawn glass tube to enter a heat preservation track for annealing, and cutting to prepare the ultra-long high precision boron-containing glass tube. According to the method provided by the invention, goodprocess stability and excellent and stable product quality are realized in the production.