In the construction of LNG module plant, the highest technical level is the construction of the core process module, The construction process requires precise positioning control measurements for a large number of mechanical equipment. This paper takes the first core process module project in China as an example, from the deck beam prefabricated stage to the equipment base erection stage, and then to the equipment installation stage, discussing the dimension surveying method about the large equipment on core process module. Based on the principle of the resection in the measurement technique, the technical method for the installation of the mechanical equipment is given.