Abstract: 24 isolates of Sphaeropsis sapinea obtained from various countries and hosts were studied on differences in cultural characteristics, growth rate in vitro, conidiospore production, conidial wall ornamentation and virulence. There were significant differences in cultural characteristics among isolates. 17 Chinese isolates could be divided into two types, while alien isolates concluded more than two types. Light and nourishment were two important factors infecting conidiospore production. All the isolates produced chlamydospores after 50 days on PDA in dark. The amount of conidia produced on sterile pine needles differed significantly among isolates. The conidial wall ornamentation could not be linked to types of isolates. The results of inoculations showed obvious differences in virulence to three pine seedlings among isolates. Most isolates could infect unwounded seedlings. To most isolates, it didn’t display an obvious link among these characteristics.