Abstract：Surface wave technique is applied extensively in engineering geological exploration and engineering testing. Existing theoretic studies have been focused on computation and forward and backward analysis，while engineering applications have been focused on geological exploration，roadbed compaction degree and groundwork bearing force testing. It is found that strong relativity exists between surface wave time domain signal and testing section¢s geological condition by means of studying on characteristic analysis of surface wave time signal. In media of isolated stone and hole，surface wave time domain signals occur distinct reflection and scatter. In the earth¢s surface with high stiffness，surface wave time domain signals exist higher mode component. In the earth¢s surface with weak layer，surface wave time domain signals behave lots of vibration mode component，and exist higher mode. When the earth¢s surface exists soft and stiff area，axis of in-phase of surface wave time domain signals has obvious transition，which makes location of soft and stiff area certain. Disturbing signals often exist in data collection，it determines type of disturbing signals(fixuping disturbing signals and random disturbing signals)，and eliminates their impact. It explains the surface wave time domain signals at the aspect of engineering geology by means of testing section¢s geological condition，and draws some conclusions on geological characteristic reflected by several typical surface wave time domain signals，which helps engineers for quickly judgement in field.
