This research mainly includes the analysis of international competitiveness of Taiwan’s environmental service industry; report on WTO and environmental issues and trends, and the stance of our country and related strategy. This research reveals three main points as follows：(1) According to RCA index, Taiwan precedes Mainland China, Malaysia, Indonesia, Vietnam, and the Philippines；while India, Singapore and Thailand are ahead of Taiwan.(2) The regression analysis shows the significant correlation between the direct investments on Southeast and the export expansion of environmental service industry. Cases of direct investments in Hong Kong and Vietnam are two most persuasive proofs to show the export expansion of Taiwan’s local environmental service industry. (3) The general score of Taiwan’s environmental service industry is 57.6, which ranks “poor.” Among the evaluations, the most disadvantaged part is the supporting of related industries, which scores only 9.4, and the index of production factors precedes above one, which scores only 13.8. Improving these two dimensions will be the main direction for advancing competitiveness of Taiwan’s environmental service industry. The management and marketing efficiency posits the highest rank for the mark of 18.4, apparently contributing to the competitiveness of Taiwan’s environmental service industry. By probing into the competitiveness of production factors, this research also discovers that future enterprises should make more efforts in order to improve the poor performance on R&D.

Environmental Service Industry, Diamond System Theory