This invention belongs to the textile weaving pretreatment technique field, which mainly relates to a kind of jutes and its weaving pretreatment mixing with other fibers. And this invention includes soakage sizing and mangling and drying steps, the character is that it also includes smearing flexible agent on the upper and under surfaces of the mangled yarn. The advantage is that this invention can reduce the coefficient of friction of the surface of the yarn effectively by smearing flexible agent on the upper and under surfaces of the mangled yarn, and because the filtering quantum of the flexible agent that filters into the inner of the yarn is reduced greatly comparing to the conventional technology, so the composition of forces between the inner fiber of the yarn won't be affected, so that the fluffing phenomena can be inhibited effectively in the course of weaving.