Abstract: Cedar blight was found in Jiangsu province, China in 1983. Seedlings of Sabina virginiana are severe damaged. Seedlings of Sabina chinensis cv. "pyrami-dalis" , Fokienia hodginsii, Cupressus funebris and C. giganied are also infected. Infections were observed by artificial inoculations with causal fungus on many other species and varieties of Sabina, Cupressus, Chamaecyparis, Thuja, Platycladus and Cryptom’eria. The causal fungus was identified as Phomopsis juniperovora Hahn on the bases of koch’s postulates. Pycnidia occur on died shoots and leavts. When embedded they become crumpent, subglobose to lens-shaped, thickened at the upper part ostiolate, brown to black and 134~378m in diameter, while the con-idiophcres are filiform, hyaline and 10-15 l-2m. The a type conidia are oblong to ellipsoid, sometimes spindle shaped with obtuse ends, continuous with 2~3 oil drops, hyaline, 6.4~11.6 x 2.5~3.9m; and the type conidia filiform, often curved as s-shaped or hooked at the upper part, hyaline, 18~241 1m. The fungus invades through wounds or penetrates epidermis without wounds on current year seedlings. The optimum temperature for mycelium growth is 23~25, and about 22 for a type conidium germination. The pH for mycelium growth ranges between 3.2 and 8.3 and about the same for conidium germination.