This paper presents a vectorization algorithm for multi-cluster and VLIW(very long instruction word) DSP and this algorithm can significantly improve the performance of some compute-intensive programs which are widely used in DSP field. Via pre-handling the chain of the instruction and synthesizing the special instruction if needed, at last the algorithm synthesizing the vectorized instruction which the DSP provided. The experimental result shows this vectorization algorithm achieves 6.60 times performance improvement on average.