Abstract: In order to improve the detection technologies of the viruses in test-tube plantlets of sweet potato, we have been rapid propagation the test-tube plantlets of ipomoea setosa in the medium “MS+IBA 0.2 mg/L” using the growing point on the stem of Ipomoea setosa that sprouting by the seeds in the medium “MS+GA3 2.0 mg/L”. Grafted the test-tube plantlets of sweet potato and the test-tube plantlets of Ipomoea setosa and cultured in the medium “MS0” in vitro, after 15 days. The leaves of the test-tube plantlets of Ipomoea setosa that grafting with the test-tube plantlets of sweet potato infected by the virus become yellowing or floral leaf. The test-tube plantlets of ipomoea setosa that grafting with the test-tube plantlets of sweet potato no virus infection can normal growth. Cultured the test-tube plantlets of Ipomoea setosa that infected by body fluid of the sterile test-tube plantlets of sweet potato through the wounds in stem in the medium “MS0” in vitro, after 15 days. The leaves of the test-tube plantlets of ipomoea setosa that infected by containing the virus body fluid of the sterile test-tube plantlets of sweet potato become yellowing or floral leaf then exsciccation. The test-tube plantlets of Ipomoea setosa that infected by no virus body fluid of the sterile test-tube plantlets of Sweet Potato can normal growth, both methods can displace the old methods that “Grafted the plantlets of Sweet Potato and the plantlets of ipomoea setosa in net room”. It has the advantages of high sensitivity, low cost, easily controlled culture conditions, not limited by season, not affected by the external environment, etc.