Many efforts have been made to develop needed technology for knowledge of management
organizations, environment policy making and finding solution for complex problems. The efforts
come to end by introduction of environmental decision support systems. The aim of this paper is the
study of concepts, studies, system design and challenges from past to present. Decision support
system was defined in various ways. Most of the EDSS reviewed (in Section 2) were developed to
provide support across all three phases of the decision-making process (i.e., intelligence, design and
choice phases) within unstructured decision contexts. The made challenges are categorized in three
categories: the challenges depend on participation of users and stakeholders in EDSS development,
tools and software challenges and success evaluation. In future, we expect widespread progress in
EDSS and especially in spatial data base, long date data base, modeling and advanced computational
techniques. EDSSs in practice by users is one of the most dominant challenges in system
development, so future researches will be on participation of users, stakeholders and environment
managers in EDSS development, user friendly tools and validation of system.