The polycarbosilane microspheres were fabricated using polycarbosilane as precursor by nano-precipitation technology. The effect of operating conditions on the size and surface morphology of the polycarbosilane microspheres was studied using SEM and TEM. The polycarbosilane microspheres were then converted to the silicon oxycarbide microspheres through oxidative curing treatment and followed pyrolyzing at 1000 °C. The silicon oxycarbide microspheres were characterized by FTIR and SEM.Highlights► Polycarbosilane (PCS) as precursor. ► PCS microspheres were fabricated by nano-precipitation. ► The size and surface morphology of PCS microspheres could be adjusted. ► Pyrolysis of the PCS microspheres produce silicon oxycarbide ceramic microspheres. ► Ceramic microspheres remain the morphology of PCS microspheres.