Abstract: This paper deals with the biodegradation of LAS.Taking the LAS degradation rate and the immobilized cell's degradation duration as experimental criteria, the optimal immobilization is determined by means of immobilizing bacterium TP-1 on the sodium alginate carrier and making cross-test. Meanwhile,the LAS degradation ability test is made with both the immobilized cell and free cell. The result indicates that the immobilized cell can obviously increase the degradation degree of LAS.