Abstract: The shell cracking of one type of micro rectangular electric connectors occurred many times during the test. Through contrast test of three groups of samples (being cleaned normally, being cleaned intentinonally and without cleaning, respectively) on the aspects of appearance, hardness, insertion force and destruction force, it was found that there were no obvious differences. All these three groups of samples did not crack under low temperature storage condition or after stable repeated plugging and pulling operation. However, the thin-walled shell of the three groups of electric connectors would be damaged easily with smaller external force. So it can be concluded that the EC-1 cleaner had no impact on properties of shell of the electric connector.