Abstract: The structure of native tree species in Nanning City was studied by means of analytic hierarchy process (AHP) on the basis of the survey data of conserving and utilizing the forest land in the city. The optimal model of tree species structure was established with quantitative analysis as the core by taking the maximum ecological and economic benefits as the goal. The results showed that it would be beneficial to promoting the productivity of forest land and forming more stable forest ecosystem if the proportion of coniferous and broadleaved tree species would be adjusted from present 68∶32 to 55∶45.