SiC ceramic matrix composites have excellent mechanical properties and high-temperature resistance, and hence attracts increasing research attentions in aerospace and other fields. Precursor infiltration and pyrolysis (PIP) is one of the most common methods for the preparation of SiC ceramic matrix composites. The synthesis of organic precursors is the basis of the PIP process. Liquid polycarbosilane (LPCS) is an ideal precursor for the preparation of SiC ceramic matrix composites by PIP process.LPCS can be prepared using the Grignard coupling reaction, while this method suffers from the problem of long synthesis route and high cost. The Wurtz reaction, as another method for synthesizing LPCS, has a shorter route and less cost. However, it is difficult to directly synthesize LPCS containing active groups because of the severe reaction conditions. Ultrasound can significantly promote the effective contact between sodium and chlorosilanes and reduce the reaction conditions in the Wurtz reaction, and some ether additives can improve the activity of the reaction groups. Therefore, the introduction of ultrasound and ether additives is expected to realize the efficient synthesis of LPCS containing active groups. In this work, an active LPCS was prepared directly from chlorosilane monomer containing active groups by using ultrasonic and ether additives in Wurtz reaction. The basic structure of the product, ceramic yield and pyrolytic properties of the transformed ceramics were characterized.