A low-velocity abnormal body upper strata under low-reduced zone is called conceal low-velocity body.If the body were enough wide and high,it were made travel time of seismic wave to delay.The delay of travel time of seismic wave will not be corrected as a result of deficiency of the delay in conventional static correction because the body is under the low-reduced zone.Thus shape of reflected events will be changed,and result in structure form will be changed.Analysis showed that it should belong remnant static time difference that change of the shape of reflected events brought by the conceal low-velocity body.But frequently the change were be mistook to bring by structure form changed the change because change of shapes of structure forms from different depth is different.If the remnant time differences were not be removed the seismic structure map were be distortion,so it will be perplex to map out the exploration oil and gas.