A series of polyaluminosilazanes （PASZ） precursors were prepared by thermal polymerization with different proportion of polysilazanes liquid oligomers and aluminum acetylacetone ［0.1%~1%（w）］ as raw materials. The continuous SiAlCN（O） fibers were obtained via the melt spinning， air pre-oxidation treatment and high temperature cracking of PASZ. The PASZ and SiAlCN（O） fibers were characterized by FT-IR， GPC， SEM， XRD and metallographic microscopy. The results show that the mass average molecular weight of PASZ is from 7 191 to 11 275 g/mol， and prepared PASZ with 0.2% aluminum acetylacetone mass fraction shows shear thinning and excellent spinning property in molten state which could be continuously prepared up to 3 km. The SiAlCN（O） fiber is amorphous aluminum-containing silicon nitride fiber and the diameter of the fiber is about 20 to 70 μm， and the fiber surface is smooth， without obvious defects such as cracks and grooves.