A specialized dynamic distillation and purification process is used and cooperated with the optimized homogenized melt and the low-temperature quenching techniques to obtain high purity As40S60 and As38S62 glass. Then an efficient extrusion method is applied to the preparation of a core-cladding chalcogenide optical fiber preform. After that, under the protection of the polymer, which is polyethersulfone (PES), the preform is drawn into the As40S60/As38S62 core-cladding structure chalcogenide optical fiber with precise proportion, eccentricity closing to zero and low loss. After the high pressure extrusion process, the defects in the core-cladding interface are nearly eliminated, and thus the fiber loss is reduced effectively. The experimental results show that the infrared transmittance of As40S60 glass is obviously improved after effective purification and most impurity absorption bands in the spectra disappear. After the surface of fiber input ends is coated the Ga layer, the standard cut-back technique is adopted to measure the attenuation of this As40S60/As38S62 fiber. The transmitting background loss is around 0.2 dB/m, and the minimum loss is about 0.13 dB/m at 4.8 μm.