Abstract: Poplar mosaic virus is a new disease in China. The cultivar "Harvard" can be regarded as very susceptible to the virus. Use of infected plants can result in volume growth being 30% below normal.The results of trials in virus infection show that 1. The virus infects Vigna uaguiculata, Nicotiana tabacum, Cucumis sativus, Tropaeolum majus, Chenopodium foetidum, Ocimum basilicum and Petunid hybrida.The symptoms appeared in poplar leaf are light brown necrotic streaks. The symptoms of poplar leaf by inoculation are black-brown spots. The twelve clones of poplar are resistant, six clones are highly susceptible and two of them are moderately suscepit ble. 2. The dilutionend point is 10_-3, thermal inactivation point 75—80℃, longvity in vitro 7 days. 3. The measurement of the threall like virus particles is 672—735nm×12—13nm.