The invention discloses a wire parameter measurement instrument. The wire parameter measurement instrument comprises a current transformer, a voltage transformer, a CPU (Central Processing Unit), a GPS (Global Position System) clock module, a display module, an environmental information acquisition module, a communication module, a man-machine interface and a power supply module, wherein the current transformer, the voltage transformer, the environmental information acquisition module, the GPS clock module, the display module and the communication module are respectively connected with the CPU; the GPS clock module is used for providing correct time to information acquired by the CPU; the communication module is used for mutually communicating said two wire parameter measurement instruments. The wire parameter measurement method comprises the following steps: printing time marks to acquired data through the GPS clock module, transmitting the data to the CPU, fusing A-terminal data with B-terminal data, figuring out resistance r, reactive resistance x and electrical susceptance b of the unit length wire, and amending according to temperature, humidity and illumination values. According to the wire parameter measurement instrument, wire parameters are precisely measured under practical running environment, and the wire parameters in each voltage rank can be in online measured without power failure.