The invention relates to a tensioner system for producing a LNG ship insulating case and a tensioning process of the tensioner system. The tensioner system is used for conducting fixation at the solidification stage after an insulating case body is glued. The insulating case body is formed by connecting a polyurethane plate with plywood located at the two sides of the polyurethane plate through gluing, and inwards-sunken right angles are formed at four end corner edges of the polyurethane plate. Corner clamping plates are mounted at the inwards-sunken right angles. The tensioner system comprises a tensioner tray and tensioner assemblies, wherein the tensioner assemblies are put on the tensioner tray. Each tensioner assembly is in a rectangle shape matched with the insulating case body andcomprises metal corner brackets and elastic components, wherein the metal corner brackets are located at four end corners, and each elastic component is arranged between the two corresponding metal corner brackets and used for providing constraining pull force. Nylon blocks are arranged on the metal corner brackets and attached to the positions, at the two sides of the inwards-sunken right anglesof the corner clamping plates and the insulating case body, of the plywood. Compared with the prior art, by means of the tensioner system and the tensioning process thereof, production dimensional precision and gluing connection strength of the case body can be effectively controlled; production efficiency is improved, and the yield is increased; the cost is lowered; and the tensioner system and the tensioning process thereof are particularly applicable to an automated production line and the like.