Strength, modulus and flexibility as three important mechanical properties for silicon carbide(SiC) fibers can be affected by diameter of SiC fiber, which is controled by specific melt-spinning process. In this study, effects of spinning temperature(T), spinning pressure(P) and winding speed(V) on diameter of polycarbosilane(PCS) fiber were studied. Mechanisms for the fiber breakage during spinning process was explored, and relationship between diameter and mechanical properties of SiC fiber was also analyz...