Abstract: Considering the influence of greenhouse environment on cultivation of cucumber, this article proposed a method of cucumber greenhouse environment decision based on fuzzy reasoning technology. Through collecting information of the main environmental factors in greenhouse such as temperature, humidity, light intensity and CO2 concentration, the system quantified their degrees of membership based on expert knowledge, calculated their conclusion value for each conclusion of knowledge in the knowledge base, and communicated with users to give the last conclusion. The system helped users to manage the cucumber greenhouse environment．

Key words: fuzzy reasoning, dynamic membership partition, greenhouse environment decision, expert system