Abstract: This paper proposes a kind of expert control method for two-variable control of temperature and liquid level in the cold-hot water mixer system. This method can set up the control rule sets according to the distinguishing features of the system and special knowledge and experience of experts. And also it can make the forward inference based on the output measurements and implement the control rules. Results of the experiments show that the expert control method can achieve better performance in control process although there is a very strong couple between temperature and liquid level and a dead time in the mixer.