A continuous polycarbosilane(PCS) multifilament was melt spun at≈300℃. Spinning was performed with a laboratory scale extrusion apparatus equipped with a multi-hole spinneret. The filament was drawn down to a diameter of 10～25μm, the mechanical stretching being applied to the filament via the take-up reel. The spinning stability was investigated by introducing the ringy spinning channel and mobile take-up reel and changing the melt spinning processing, in order to obtain continuous PCS-derived silicon carbide fiber with fine diameter,lower diameter's dispersion rate and higher tensile strength. The results show that increasing the cooling temperature within the 180～200℃ range, introducing ringy and downward airflow by a special spinning channel, controlling a proper spinning line of about 90cm in length, enhancing fibers' gathering and controlling the stabilities of spinning conditions can improve the spinning stability availably.