Abstract: To estimate the significance of Pinus massoniana plantation in biodiversity conservation, the Malaise trap method was used to investigate the insect community composition and diversity in P. massoniana plantation and the adjacent natural forest in Shiwandashan Nature Reserve, Damingshan Nature Reserve and Huaping Nature Reserve, Guangxi. Permutational multivariate analysis of variance(PERMANOVA), nonmetric multidimensional scaling(NMDS), similarity percentage(SIMPER) and one-way ANOVA were conducted to explore the differences of insect community composition and diversity between P. massoniana plantation and the adjacent natural forest. The results showed that a total of 10305 insects were collected from 3 study sites, belonging to 10 orders and 102 families, and Diptera, Hemiptera, Lepidoptera and Hymenoptera were the dominant groups. PERMANOVA and NMDS analysis showed that there were significant differences in insect community composition among 3 study sites, and there were also significant differences in insect community composition between P. massoniana plantation and the adjacent natural forest in each study site. SIMPER analysis further indicated that Cecidomyiidae, Sclaridae, Lauxaniidae, Tipulidae, Mycetophilidae, Limoniidae, Dolichopodidae, Calliphoridae, Phoridae, Chironomidae, Asilidae, Ichneumonidae, Eupelmidae, Braconidae, Aphididae, Cicadellidae, Derbidae, Delphacidae, Fulgoridae, Cicadidae, Scolytidae, Chrysomelidae, Coccinellidae, Crambidae, Gracilariidae, Oecophoridae, Gelechiidae and Immidae were the major families that differed between P. massoniana plantation and the adjacent natural forest, which is probably related to microenvironment in forest or plant species community composition. There was no significant difference in species richness index, Simpson index, Shannon-Wiener index and Pielou index at the family level between P. massoniana plantation and the adjacent natural forest. The results suggest that P. massoniana plantation is not the "desert" of biodiversity and plays an important role in biodiversity conservation, but cannot replace the role of natural forest in maintaining regional biodiversity.