Abstract: To meet the needs of the research and application of the cooperative distributed problem solving （CDPS）, we develop an agent oriented programming language 1 . DL-1 language is composed of two parts: DL-1/system and DL-1/agent. DL-1/system is aimed at describing administrative structure of CDPS systems explicitly. DL-1/agent aims at describing agents in CDPS systems, and allows users to describe problemsolving structures of CDPS systems implicitly at the same time.