Fuente: WIPO "hemp" The invention relates to a pretreatment process of anti-tensile dyeing sisal hemp yarns. The pretreatment process comprises: 1) placing a sisal hemp raw material in an environment with a temperature of 25+/-5 DEG C and a humidity of 55-60% for 40-48 h; 2) carrying out water washing on the sisal hemp raw material; 3) spraying with a hemp softening agent, wherein per 100 kg of the sisal hemp are added with 10-12 kg of the hemp softening agent; 4) placing the sisal hemp in an environment with a temperature of 25+/-5 DEG C and a humidity of 55-60% for 40-48 h to completely soften the sisal hemp fibers; 5) spraying the sisal hemp obtained in the step 4) with white oil, and placing the sisal hemp in an environment with a temperature of 25+/-5 DEG C and a humidity of 55-60% for 20-28 h, wherein per 100 kg of the sisal hemp are added with 10-13 kg of the white oil; and 6) immersing the sisal hemp obtained in the step 3) in a sodium hydroxide solution for 10-20 min at an immersion temperature of 20-25 DEG C, wherein the concentration of the sodium hydroxide solution is 10-15 g/mL. According to the present invention, with the pretreatment process, the complete softening of the sisal hemp fiber can be ensured, the sisal hemp product can have good texture, the finish of the sisal hemp fibers can be improved, and the elasticity and the flexibility of the treated sisal hemp fibers can be improved.