Abstract: Deuterated polystyrene (DPS) and deuterated polyethylene fibers are the important fuel container materials of the neutron emission generated during Z-pinch experiment. In this work, fibers with the diameter of 30-100 μm were prepared by micro melt spinning. According to the study on mechanical properties of polystyrene (PS) and DPS fibers, when the fixed percentage of elongation is 1%, the stress relaxation rate of PS fiber is small. PS fiber shows good dimensional stability at different external forces. The tensile strength and elongation increase with the diameter of the DPS fiber decreasing. When the diameter of the fiber decreases below 100 μm, the tensile strength rapidly increases. DPS fiber shows good dimensional stability at small external force. The creep deformation and stress relaxation behaviors of DPS fiber have the same change tendency with PS fiber.