An Automatic Telephone Line Testing System has been designed and implemented to provide means for making rapid and accurate transmission measurement on telephone tranks using micro-processor. The system consists of a Central Unit and Romote Unit. All measurement sequences are under command of the Central Unit, once the system starts. Thus, attenuation and cross-talk of telephone trunks are automatically measured and recorded. The proposed instrumentation system, system hardwares and associated softwares are discribed indetail. This system is only prototype and has some problems in actual application.