As a preceramic polymer to silicon carbide fibers, polycarbosilane (PCS) should have both a relatively higher melting point (m.p.) and a relatively good spinnability. However,to increase m.p. means a rigid requirement for the synthesis conditions. To solve this problem, we firstly obtain a higher m.p. (>280℃) PCS fraction via fractional precipitation,and then add 10-30wt% of a lower m.p. fraction to above PCS,thus obtain PCS mixture,then,both have a higher m.p. (>250℃) and a relatively good spinnability.