Provided is a system partition system and a construction method thereof. The system partition system comprises an upper steel support, a middle finished product system partition and a lower metal base supported at the bottom of the finished product system partition. The upper steel support is arranged between a suspended ceiling board and an upper floor. A suspended ceiling system is further arranged between the suspended ceiling board and the upper floor. The upper part of the finished product system partition is in bolted connection with the bottom of the upper steel support. The lower part of the finished product system partition is arranged on the metal base. The suspended ceiling board is arranged in the bolted connection part of the finished product system partition and an upper part steel frame. The metal base is arranged in a floor system. The floor system is arranged on a lower floor. The upper steel support comprises a main support structure and a double-layer paper surface gypsum board arranged on the outside of the main support structure. Rock wools fill the main support structure. The bottom of the upper steel support is sealed by a core-board. The metal base is a galvanization square steel arranged at the bottom of the finished product system partition in a spacing mode. The system partition system and the construction method thereof have the characteristics such as safety and good applicability and good promotional value and practical value, and the good economic benefit can be produced after extensive application and promotion.