Abstract: The conifer and broad leaf mixed forests at different succession stages of middle-aged forest, near-mature forest, mature forest, and old growth forest in Changbai Mountains, Zhangguangcai ridge of Jilin Province were studied in order to investigate the biodiversity related characteristics such as species composition, spatial relationship, dead wood, invasive species, and so on. Combined with the analytical status on biodiversity evaluation at home and abroad , an initial biodiversity evaluation index system with three levels was constructed for conifer and broad leaf mixed forest and a total of 25 representative 3rd-level indices were selected. Principal component analysis was then used to screen the indices and the final evaluation index system with 17 evaluation indices of 3rd-level was obtained. The Analytical Hierarchical Process together with export scoring was applied to determine the weights of the evaluation indices and a biodiversity evaluation model for mixed conifer and broad leaf forest was finally constructed, which can provide basis for the evaluation of biodiversity in conifer and broad leaf mixed forest and the determination of related forest biodiversity protection policies.