The results indicated that pine wilt disease was a disease complex involving the nematodes and bacteria. It was reported in this paper that the dosage of certain antibiotics in which growth of the B619 bacterium was inhibited in the tissue of the testing seedlings of P.thunbergii which was screened by using the systematic property of the antibiotics. Then under non aseptic conditions, inoculation of pine wood nematode on the testing seedlings was made. Results showed that no wilting symptom appeared on the seedlings cultured with antibiotics’ solution, but all the seedlings cultured with aseptic water were wilted; After the test all the seedlings cultured with antibiotics solution were checked. And living nematodes existed in tissues of all checked seedlings. The results not only further demonstrated that the disease was a disease complex involving the nematodes and bacteria, but also showed that the pine wilt disease could be controlled by inhibiting the pathogenic bacteria for the first time. The results of this paper formed bases to develop new ways in controlling the disease and diagnosing the disease in the early phase, to culture new transgenic pines with anti pine wilt disease genes and to further study the mechanisms of the pine wilt disease.