Abstract A basic scheme for detecting subsurface targets with EM pulse of nanoseconds and an especially developed travelling-wave antenna of high quality are described. The antenna is a sort of sector antenna with structure of three layers, which possesses higher radiation efficiency and better travelling-wave properties. A fine resolution graphic system and a high speed display are employed in terminal processing. Metal pipes burried about 1m under the earth can be detected and clearly displayed. High resolution and burried about lm under short processing time of the system, compared with other similar devices make it suitable for engineering use.