Indirect economic losses associated with alien invasive species to forest ecological system are mainly caused by the decrease of commonweal function. The indirect economic losses are in proportion to the decrease of forest volume growth caused by alien invasive species. Based on the data from forest inventory and typical case studies, indirect economic losses caused by alien invasive species to forest ecological system in 2000 are figured out. Indirect economic losses are ¥15443.43 million. Losses caused by alien conifer insects, such as Bursaphelenchus xylophilus, Hemiberlesia pitysophila, Oracella acutus, Dendroctonus valens and Matsucoccus matsumur are ¥13264.07 million, comprising 85.89 percent of the total losses, while losses caused by alien broad-leaved insects such as Hyphantria cunea are ¥742.90 million, comprising 4.81 percent. Losses caused by alien pathogens and other alien insects are ¥1436.46 million, comprising 9.30 percent of total losses.