The invention relates to the field of textile production, in particular to aramid fiber blended yarn and a preparation technology thereof. The aramid fiber blended yarn is characterized in that 1414.Kevlar aramid fiber, 1313.T450 aramid fiber, flame retardant glue, modacrylic, combed cotton, conducting fiber, chinlon and tencel are adopted as raw materials, fineness degrees of the materials are respectively 1.7, 2.2 and 3 deniers, any four materials in the raw materials are selected as main raw materials, the length of the four materials selected as the main materials at will is 48-51 millimeters, the lengths of the remaining auxiliary raw materials are respectively 28 millimeters and 38 millimeters. Compared with the prior art, the processing technology is simple in process, produced products have good performance such as high strength, high modulus, high-temperature resistance, acid resistance, alkali resistance and light weight, are high in strength, and can solve the problem that a machine part is damaged easily. The development of the aramid fiber blended yarn and the success of matched military supplies can bring markets for enterprises and innovation conceptions. Meanwhile, firmness, flame-retarding performance and anti-static electricity capacity of the military supplies are changed in nature compared with prior fiber blended yarn.