The prize fish green cultivation project of Rizhao Wanzefeng Fishery Co., Ltd. at Yellow Sea Cold Water Mass is one of the first major projects for upgrading of the old development mode to the new one in Shandong province. The planned marine area is 20km2. Site investigation is the first basic work for the construction project, and also the important basis of project site selection, design and construction. With effectively utilizing limited resources, proper verification, careful construction, innovative renovation of the drilling ship, and placement of the deep-sea casing with the gravity guide device, site investigation was successfully completed for the project, providing experiences for offshore deepwater investigation works.