In this paper, we analyze and compare the properties of three kinds of high fre- quency board to wire connectors which are horizontal K-type connector vertical K-type connector, and subminiature modular plug-in mini (SMPM) connector. The S-parameters of these connec- tors were simulated through the High Frequency Structure Simulator (HFSS) software. Using these connectors, three kinds of evaluation boards (EVB) were designed for measuring the high frequency performance of the connectors. The S-parameters of these EVBs were measured and verified through the network analyzer, and the impedances were also measured through the time domain reflector (TDR) The bandwidth of the SMPM connector is about 19 GHz, the bandwidth of the vertical K-type connector is about 23 GHz, and the bandwidth of the horizontal K-type connector is above 25 GHz. The board to wire horizontal K-type connector is more suitable than the other two connectors for 25 Gb/s transmission applications.