Abstract: In order to fully rounded understanding experience and lessons gained during Japan’s offshore hydrate production tests and providing the necessary references for the hydrate research and development(RD)in China,the paper systematically introduced Japan’s second offshore hydrate production test,compared and analyzed the technologies and problem of two production tests,and summarized the development of main production technologies in Japan.Research showed that technical problems such as sand production occurred in two production tests,and there were still significant deficiencies in several aspects, including drilling and completion,sand control,artificial lift,monitoring and in situ test.Combined with Japan’s progress and deficiencies in offshore gas hydrate development technologies,some suggestions were put forward,such as to closely coordinate RD,to form a development device system with independent intellectual property rights,and to develop the specifications for exploration and pilot production tests.