Abstract: Un-crimped energy is one of important parameters in cellulose acetate cigarette tow production. The reliable and stable testing data is very important to process control and tow quality. Different test results were obtained by application of different clamps including trapezia and sine shaped clamps. Testing results have been showed that the clamp significantly impacts the testing results of un-crimped energy. Mini-tab was used to analysis the standard deviation under the application of different clamps. Suitable clamp was selected to decrease the fluctuation in testing. More reliable and stable testing results were gotten by sine shaped clamp application.