The invention relates to an installation method of an angle area insulation module used for an enveloping system on an LNG ship. The installation method includes the following steps that the angle area insulation module is manufactured, and the bottom surface of the angle area insulation module is coated with resin; the angle area insulation module coated with the resin is transported to the position below the to-be-installed position through a flat trolley; a special lifting tool is installed on the inner side of a 90-degree angle of the angle area insulation module; a crane is started, and awinch hook of the crane is hung on the special lifting tool; and the crane is operated, the angle area insulation module is lifted to the installation position in the enveloping system, position fineadjustment is conducted through manpower until the angle area insulation module is accurately placed in place, and after the special lifting tool is detached, the angle area insulation module is installed in the enveloping system as an insulation layer. The installation method and the tool are matched together, the angle area insulation module is quickly moved and installed, and the method has the advantages that operation is convenient and simple, and installation is quick and accurate.