Abstract: Subsea two-phase wetgas flow meter is the first domestically developed flow measurement device based on ultrasonic technology, is a key equipment for marine oil underwater production systems, which can overcome the large deep water pressure, high seal requirements, strong corrosion, strong pressure and large range of flow changes and other harsh conditions, the organic combination of differential pressure and velocity flow measurement principle is realized by using Venturi technology and ultrasonic technology, and flow measurement can be realized without separation of gas and liquid. As a key technological equipment for deep-sea development, it has broken the technological monopoly of the same equipment in foreign countries and reached the advanced level in the world due to its low cost and good sealing performance. In its development process, China Classification Society (CCS) Tianjin Branch participated in its inspection and equipment certification. As there is no complete referable inspection basis in China, in the process of design, production and test, the standard collection and summary are also carried out, and every inspection work is fully implemented.In this paper, several typical test procedures are described, the relevant procedures and points are introduced, related standards are sorted out, a preliminary verification system of the Classification Society is formed, it also ensures that the subsea twophase wetgas flow meter can meet the research and development requirements.