Setting a quantitative conservation target comprises an important step in systematic conservation planning. This paper outlines a first attempt to calculate quantitative conservation targets for selection of national parks, wildlife refuges, and protected areas in 21 terrestrial ecosystems at the national level. To formulate and calculate targets, we further developed Pressey and Taffs's formula (2001) and included baseline target, natural rarity and potential ecological vulnerability (PEV) in ou r formulation. The PEV was defined as the potential impacts resulting from exposure to main threats plus ecological sensitivity of any land tract without considering adap-tation. Our results showed that the minimum and maximu m conservation targets for selection of national parks, wildlife refuges and protected areas as percentages of the area of each terrestrial ecosystem were between 1.44%-3.17%, 3.87%-8.08%, and 6.36%-13.27%, respectively. We showed how to design an effective network of three management categories including the fu l l range of terrestrial ecosystem types within the country. Na-tionally and under current conditions, we found that the Moderate-Desert Woodland & Shrublands and the Cold-Desert Steppe Scrubland ecosystems required the most and least attention, respectively. This finding provided additional support for the establishment of a representative, comprehensive and balanced network of protected areas in the country and finally a fundamental guide for effective ecological conservation and environmental management.