Ethanol solution was employed as a solvent for extracting chlorogenic acid (CGA) from Eucommia ulmoides leaves, and HPLC was used to determine the concentration of CGA in the extraction liquid. The process variables, such as the ratio of liquid to solid, the ethanol concentration, the extraction temperature and extraction time, were investigated in detail. The optimum parameters were as follows: ratio of liquid to solid of 10 mL/g, ethanol concentration of 60%(?), extraction temperature of 60℃ and extraction time of 40 min. Under the optimum conditions, the extraction yield of CGA reached up to 90.21%. The infusion rates of CGA at different temperatures were measured and the rate constants of infusion were calculated and obtained. The results indicated that the extraction of CGA in ethanol solution was controlled by internal diffusion. The extracting process was satisfied with the internal diffusion kinetic model, and the apparent activation energy was 11.46 kJ/mol.