The invention relates to a method for using a double screw extruder to prepare celluloses/ionic liquids spinning solution and the preparation comprises that the celluloses are uniformly mixed with the ionic liquids according to the weight ratio of 5:95 to 25:75, and then the mixture is put into the double screw extruder which has two vacuum orifices and the screw length diameter ratio of which is 36:1 to 60:1, the control range of temperature is 40 to 120 DEG C, and the light brown and transparent celluloses/ionic liquids spinning solution is formed after strongly mixing and dissolving for 8 to 40 minutes and vacuum dehydration; the obtained celluloses/ionic liquids spinning solution is supercharged by a booster pump and sprayed from a spinneret after coming into a metering pump by a pre-filter, and then cellulose fibers are formed by a plurality of steps such as solidification, washing, cutting and drying, etc. The invention not only shortens the dissolution time of the celluloses but also leads to the more fully mixing and dissolving of materials, and achieves the purposes of energy-saving, high efficiency, decreasing degradation and improving the quality of spinning original solution, so the industrialization becomes easier.