Abstract: The material flow ira a logging system can be divided into wooden material flow, biomass flow, nutrient flow, soil flow and water content flow. Energy flow was the force to push material flows and their transformation. The wooden material flow is consisted of three sub-flows of input, lost and output. The flow showed that the material flows in a production process and between production stages could be applied to analyze the efficiency of timber resources and the environment burden. The energy flow included five sub-flows of input, output, added, lost and recovery for other use. The flow showed that the energy flows in a production process and between production stages could be applied to analyze tbe unil energy consumption and the energy efficiency. The relations among the flows of different materials in the system and the coupling relation between the material flow aud the energy flow in the system were fbund in the study of log harvesting productiin process. The study provided the basis for further researches on the ecology-based logging operation syslem.