Eucalyptus camaldulensis is one of the most widely planted eucalypts in the world. However, rich extractives in E. camaldulensis wood leads to serious defects such as amount of pulping wastewater, lower bonding strength, bad finishing effect, and the wood extractives is considered as the key negative factors. Therefore, the leaching characteristics of wood extractives was studied bymathematicalmodel according to fuzzy theory. Theresultsshowed thatthe kinetics of wood extractives were divided into three phases: the rapidly leaching stage, the slowly leaching stage, the equilibrium leaching stage. The reaction of wood extractives leaching from E. camaldulensis biomass could be considered as a first-order reaction. Theorder of reaction was 1.02, the activation energy ofreaction Ea=14549.86J/mol, and the pre-exponential factorA=20.48min-1.