Abstract: The relationships between spatial distribution pattern of mistletoes and host species diversity,composition and related characteristics are critical to understand intraspecific relationship and forest community structure.To compare the infection prevalence (proportion of hosts infected),infection intensity (the mean numbers of mistletoes on every host tree) of mistletoe between polyculture and monoculture plantations,the spatial distribution of mistletoes in different plantations was investigated according to the plots surveys in Xishuangbanna,southwest China.The spatial structures of different mistletoe species in three different life stages (seedling,juvenile and adult) in every plot were evaluated by aggregation index,the average crowding degree,Lloyd's patchiness index,and Morisita's dispersion index,etc.Pearson correlation and Spearman correlation were also used to analyze the relationship between infection intensity of mistletoes and the height,crown diameter,DBH,abundance of host trees.The results indicated that mistletoe infection prevalence decreased at 67.09 %,66.35 % and 40.48% respectively by the increase of host trees diversity.The infection intensity of mistletoe was positively correlated with the height,crown diameter,DBH and abundance of host trees (r=0.409 and 0.455 respectively),indicated that mistletoes prefers to infecting bigger host trees and hosts with higher dominance.It was found that mistletoes showed a clustered distribution pattern,and the degree of clustered decreased when mistletoes growing up.It was also suggested that to increase the diversity of the hosts in the plantation may be a good way to reduce mistletoe infection prevalence,and to increase the productivity and efficiency.