Disclosed is a system and method for static and dynamic positioning or motion control of a marine structure by using real-time monitoring of at least one of a mooring line, marine environments, 6-dof movement of a marine structure, a tank state, a ship topside, the seabed, or their combinations. The static and dynamic real-time monitoring data of the mooring line is obtained and processed for positioning the marine structure or controlling and managing a motion thereof. Here, 1) a tension of a mooring line is measured by means of real-time monitoring of the mooring line, 2) various marine environment elements such as wind direction, wind speed, air humidity, atmospheric pressure, atmosphere temperature, cloud height, visibility, ocean wave, wave height, sea current speed, sea current direction, rain or the like are measured by means of real-time monitoring of the marine environments, 3) 6-dof movement of the marine structure is measured by means of real-time monitoring of the marine structure, 4) ullage and sloshing data of various tanks in the marine structure are measured by means of real-time monitoring of tank states, 5) damage and life of pipes, facilities or the like located at a ship topside of the marine structure are measured by means of real-time monitoring of the ship topside, 6) damage and life of umbilical cables, pipes, pumps and valves located on the seabed are measured by means of real-time monitoring of the seabed, and suitable static and dynamic positioning or motion control and management may be automatically performed based thereon.