Objective To optimize extraction technology of totals flavonoids from Platycladi cacumen. Methods With extraction rate of total flavonoids as dependent variable， ethanol concentration， solvent volume and extraction time as independent variables， Box-Behnken response surface methodology was used to optimize of extraction technology. Results Optimum process parameters were obtained as followings：15.70 times the amount of 75.44% ethanol， extracted 2 times with 86. 46 min per time. Extraction rate of totals flavonoids was 1.6728%. Conclusion This optimized technology was stable and feasible. The predictive value of mathematical model and the experimental observation value was fitted.