A melt-spinnable polyaluminocarbosilane was synthesized via the crosslink reaction between Si-H and acetylacetone aluminum(Ⅲ) by using low-molecular-weight solid polycarbosilane and acetylacetone aluminum(Ⅲ) as starting materials. The effects of reaction conditions on the numberaverage molecular weight, softening point and structure of polyaluminocarbosilane were investigated, and the relationship between the extent of crosslink reaction to the spinnability of polyaluminocarbosilane was also discussed. It was found that elevating the reaction temperature or prolonging reaction time would lead to an enhanced extent of reaction, a gradually decreased acetylacetonate and an increased crosslinked structure of Si-O-Al, resulting in poorer spinnabilty. Polyaluminocarbosilane with softening point of 206~221 ℃, Al wt%=068% and good spinnability was successful synthesized at the optimized reaction conditions of the temperature at 370 ℃, the reaction time at 4~6 h and the mass ratio of acetylacetone aluminum(Ⅲ) at 8 wt%.