Subsea pipeline is the lifeline of the offshore oil & gas field. More and more pipelines have reached their designed life with the increase of the service time. Geophysical equipment acquired the date of the free span, exposure and buried condition for the subsea pipelines. The subsea pipeline assessment system assessment the critical length and fatigue life of free span. By knowing of the condition of those lines in service, the operation risk was decreased and the safety of the subsea pipelines was increased. The support of maintenance for the owner of the subsea pipelines was also offered.