The resistant difference among different main pear cultivars in Anhui Province to pear rust caused by Gymnosporangium haraeanum was significant. According to disease index and diseased leaves of susceptible cultivars, the niche breadths of hosts were 0.7555 and 0.7951, respectively. The niche breadths of horizontal and vertical space of each cultivar were approximate to 1. The result shows that the infection of G. haraeanum was a random distribution.