Dynamic changes of customer satisfaction is very important to service enterprises, especially telecom ones. Malmquist Index based on DEA model was introduced. A new method to evaluate dynamic changes of customer satisfaction in telecom enterprises is proposed. From three aspects, pure technology efficiency, technology changes and principle factor production efficiency, dynamic changes of customer satisfaction in some telecom firms were evaluated by using the Malmquist Index.  It is suggested that telecom enterprises be improve their customer satisfaction by technology innovation and technology efficiency.