Geographic location of underground cable is important information in urban construction and power operation and maintenance. Ground penetrating radar is always used in detection for directly buried cable, but the influencing factors of its detection effect for underground cable is unclear. GprMax forward modeling method is used to analyze the ground penetrating radar echo image of underground cable， including buried depth, soil dielectric constant, antenna center frequency, pipeline material and cable channel structure. Furthermore an experiment is carried out to compare the ground penetrating radar image of cable, metal and PVC pipes at 0.4 GHz and 0.9 GHz antenna center frequency. Finally a field test for underground cable is carried out. There is a distinctive hyperbola in the ground penetrating radar image. The hyperbola shape is mainly influenced by burial depth and soil dielectric constant. It is difficult to distinguish different material pipeline based on the hyperbola shape. The fine sand and cover plate around underground cable can weaken the echo signal, and lead to hyperbola layering. In order to obtain good detection effect, it needs to detect the whole cable channel instead of the cable with 0.4 GHz center frequency antenna.