Both the Chenopodium quinoa and Vicia faba were respectively infected with two Broad bean wilt virus 2 (BBWV-2) isolates, PV131 and P158, and their cytopathological changes were observed by transmission electron microscope. In the PV131 isolate infected C. quinoa cells, the membrane proliferated and contained vesicles and electron-dense materials. The extensive proliferation of membrane might act as the viral replication center. Viral particles distributed in the cytoplasm and some of them accumulated into crystals or aggregated into tubules. The diameter of the tubule was about 75 nm and there were nine viral particles on the transverses section. The similar data were got from the other three kinds of infected mesophyll cells but PV131 and P158 virions did not accumulate into crystals in V. faba cells. All the observations indicated that the differences of pathogenicity between PV131 and P158 isolate were determined by their genome but not the host types.