The invention discloses a weighted fracturing fluid with low guar gum concentration, and belongs to the field of petroleum chemical engineering. The fracturing fluid comprises, by weight, 0.2-0.45% of hydroxypropyl guar gum, 20-45% of a weighting agent, 0.05-0.15% of a bactericide, 0.5-1% of an anti-swelling agent, 0.12-0.2% of sodium carbonate, 0.3-0.6% of a pH regulator, 0.5-0.8% of a cleanup additive, 0.5-2.0% of potassium chloride, 0-0.1% of a temperature stabilizer, 0.5-0.8% of a cross-linking agent, 0.001-0.01% of a gel breaker, and the balance of water, wherein the organic boron cross-linking agent is prepared through the following steps: adding 10-16wt% of glycerol to 30-50wt% of water, uniformly mixing glycerol and water, slowly adding 15-25wt% of borax while stirring, uniformly mixing the obtained solution and borax, adding 10-17wt% of sodium gluconate and 3-7wt% of sodium lactate, stirring above materials in a 40-60DEG C reaction kettle for 1-3h, and adding sodium hydroxide to adjust the pH value of the above system to 7. The weighted fracturing fluid provided by the invention has the advantages of low use amount of guar gum, easy gel breaking and backflow, effective reduction of the construction pressure of well heads, and excellent performances.