The legislative purposes of several environment-related acts including 「Natural Environment Conservation Act」include the conservation of biodiversity. These acts have adopted command-and-control systems, divided as the species-oriented approach and the habitats-oriented approach. These acts, however, have paid little attention to ecosystem restoration in the aspects of biodiversity conservation. This article presents some legal challenges to ecosystem restoration as a new approach to biodiversity conservation. First, it is necessary to define the legal meaning of ecosystem restoration. If it is difficult, its scope should be made clear by specifying its aims, consideration factors, criteria and methods. Second, the principles of ecosystem restoration should be established. In restoring ecosystem, the specific characters and biodiversity of the ecosystem should be considered seriously. In certain circumstances, adaptive management should be employed. Third, who should conduct ecosystem restoration activities, and who should pay the cost of restoring the ecosystem? As a rule, polluter-pays principle should be applied. If there are no polluters or it is impossible to identify the polluters, beneficiary-pays principle or shared responsibility principle may be adopted. And it is required that many interested parties including the State, local governments and community people participate in ecosystem restoration activities. Fourth, what ecosystem should be restored? The objects and priorities of ecosystem restoration should be chosen. To this end, it is necessary to periodically check and monitor ecosystems. Finally, the guidelines on ecosystem restoration should be made, and it is necessary to manage the restored ecosystems continuously.