The article aim was to study the maximum extraction conditions of flavonoids from Ginkgo biloba by water. With dried Ginkgo biloba powder as material and water as solvent, by using response surface methodology, the effects of extracting temperature, extracting time and ratio of material to solvent were studied, and then the regression model was established to study the extracting condition. The result of fractional factorial design indicated that extracting time and ratio of material to solvent played important roles in flavonoids extracting. The regression model of extraction rate(Y1) to ethanol concentration(X2) and ratio of material to solvent(X3) was Y1 = 6.423667 + 0.161*X1 + 0.68425*X2-0.52375*X3-0.660083*X1*X1+0.1745*X1*X2 - 0.6575*X1*X3 - 0.534583*X2*X2-0.0135*X2*X3-1.527583*X3*X3, and the optimum conditions were ratio of material to solvent 1∶13.76, time 3.70h, and temperature 93.37℃. The maximum extraction rate predicted by the model was 6.754%. Final results show that response surface methodology was a good method for optimizing extraction conditions of flavonoids.