The interest in environmentally conscious manufacturing has increased due to the goal of reducing environmental impacts and resource consumption in manufacturing system. However, little pays attention to the issue in the production operational process of manufacturing system. This paper introduces a new tool that integrates environmentally-conscious information into the job assignment activities. The objective of the tool is to assist production managers in their decision-making regarding resource-saving and environmentally-friendly assignment schemes. The system framework is built up with six components. Furthermore, the two key issues of the system are presented including the description of the information flow in the function level and the establishment of models in the model layer. The prototype of the system is developed and the demonstration is fulfilled in the gear machining shop floor.