A measurement system for the testing of transmission lines was designed and implemented, which greatly reduced the testing time, avoided the arrangement of cables, and hence enhanced the efficiency of the test. The measurement system, consisting of a center station, a current acquisition and transmitting node, a voltage acquisition and transmitting node, etc., is based on wireless communication. A high-speed wireless bridge working at 2.4GHz together with a clock synchronization module based on the IEEE1588 communicating protocol was employed for the communication and time synchronization. The data storage, waveform display, data analysis, automatic report generation and other functions have been achieved in the measurement system. A practical test was done at a 500 kV substation in Jiangsu Province of China, which proves the validity and effectiveness of the measurement system.