Chlorogenic acid was extracted from sweet potato stems and leaves by microwave-assisted ethanol extraction method. The binomial mathematical model was obtained to optimize the extraction process by response surface methodology with four-factor, three-level based on single factor experiments with extraction time, temperature, solid-liquid ratio and ethanol concentration as the influence factors and the extraction yield of the chlorogenic acid as response value. The results showed that the optimum parameters were as follows: the extraction time was 25 min, the extraction temperature was 64.5 ℃, the solid-liquid ratio was 1∶35 g/mL and the ethanol concentration was 45%. Under the optimal conditions, the maximum extraction rate of chlorogenic acid was 3.4421 mg/g, which was close to the predictive value. The response surface methodology is applicable for the optimization of microwave-assisted ethanol extraction of chlorogenic acid from sweet potato stems and leaves.