When traditional single derrick drilling platforms and drilling vessels working， the connection and lowering of other parallel auxiliary pipelines are unable to simultaneously complete， therefore， a concept of offline operation in the moon-pool area is proposed. A power device on the blowout preventer trolley in the moon-pool area is installed which can lift， lower， and suspend pipelines. Combined with the original drilling system’s supporting equipment such as catwalk machines， pipe racking machines， and iron roughneck， the installation， lowering， and suspend drill string， casing string， and other pipe strings in the moon-pool area can be achieved. As a result， when the ocean single derrick drilling platforms and drilling vessels working， the connection of pipe strings in the moon-pool area can be operated parallelly， which can save a lot of drilling auxiliary operation time and greatly reduce the drilling cost.