Abstract: An acrylonitrile-butadiene-styrene (ABS) resin was prepared through a self-developed twin-rotor continuous extruder. The effect of blending condition on mechanical properties of ABS resin was investigated, and the mixing ability of extruders was evaluated by POLYFLOW software. The rheological behavior and microstructure of ABS resin were characterized to investigate the effect of blending condition on the micro-morphology of rubber particles. The results indicated that the dispersive and distributive mixing abilities of the extruder were improved with an increase of rotor speed. As a result, the aggregation of rubber particles was reduced and their dispersibility was enhanced. When the rotor speed was set to 400 r/min, the tensile strength, flexural strength, flexural modulus and impact strength of ABS resin were improved by 16.8 %, 15.4 %, 30.7 % and 7.7 %, respectively. However, at the rotor speed of 500 r/min, the tensile strength, flexural strength, flexural modulus and impact strength decreased by 7.6 %, 7.5 %, 21.8 % and 32.6 %, respectively, compared with the sample obtained at the rotor speed of 400 r/min. This may be due to the internal grafting of rubber particles caused by an intensive shear effect.