In order to resolve the differential impedance of electric connector is relatively small and discontinuous at the R & D stage, the optimization scheme which is composed of the replacement of the dielectric material and the modification of the contact and the medium size based on the theory of signal integrity are proposed. The HFSS high frequency electromagnetic field simulation software was used to optimize the contact pin diameter（W1）and fit lengths of contact and dielectric (L1). When the pin diameter is 1.1 mm, the simulation value of the differential impedance of connector is 100±10 Ω and L1 has little influence on the simulation value of differential impedance of connector. The improved connector was processed and the differential impedance test was carried out. The test results show that the differential impedance range of connector is from 84.46 to 90.68 Ω before improvement and from 92.6 to 105.3 Ω after improvement, differential transmission eye diagram meets typical highspeed transmission electric connector signal integrity transmission requirements after improvement.