The constructivist learning environment was designed on three perspectives: pedagogical, social and technological. A group of 24 trainee teachers used the environment and participated in the formative evaluation. Results showed that the trainee teachers liked the design specifications and perceived the learning environment to be useful. The purpose of this paper is to describe the design specifications, implementation processes and formative evaluation results of the learning environment. Issues and implications for designing web-based learning environments are discussed. (Contains 1 table and 1 figure.)