Insertion-extraction and wear can cause microscopic topography changes in the contact surface of the electrical connector contacts, reducing contact performance and reliability. According to the structural characteristics of the electrical connector contacts, the test circuit was designed and the insertion-extraction test was carried out. The test results show that: ①In the single insertion-extraction process, the insertion force and separation force are similar to the "step square wave" variation; as the number of insertion-extraction increases, the insertion force value increases slowly; after 300 insertion-extractions, the insertion force value is basically stable, but its fluctuation is obviously increased; ②As the number of insertion-extractions increases, the contact resistance value increases slowly, but the fluctuation range gradually increases, showing an unstable trend; ③The main wear form of the connector jacks and pins are different, the jack is worn for plowing, and the pin is adhesively worn. The results show that the influence of the insertion-extraction process on the contact performance of the electrical connectors is not only reflected in the increase of the contact resistance, but also the contact resistance of every electrical connector contacts is fluctuated over a wide range, which may result in the problem that While the other electrical connector contacts are in reliable contact, the contact resistance of one of the pairs is too high. It brings hidden dangers to the reliable contact of the electrical connectors.