Randomly methylated- β-cyclodextrin (RM-β-CD) was used as phase transfer catalysis to separate citral from Litsea cubeba oil by addition reaction and hydrolysis reaction. The optimum separation conditions were obtained by single factor experiment design and Box-Behnken experiment design. The purity and yield of citral were 96.50% and 86.60%, respectively, which was gotten under the optimum conditions of reaction time 3.3 h, RM-β-CD amount 0.65% (molar fraction) and reaction temperature 15.0 ℃. Predicted value was in accordance with actual value. This proposed method was used to separate citral from Litsea cubeba oil with convenient and had high efficient advantages.