Abstract: Due to the restriction of crude oil transportation and production power sources, the exploration wells in offshore oilfields can be hardly transformed into development wells for production.As a result, huge exploration investment cannot be effectively converted into development investment and the high disposal cost is increased.The plan of constructing a new production platform based on the location of exploration well and the platform optimization plan without considering the location of drilling well were prepared according to the concept of exploration-development integration.Then, they were compared.The total drilling footage of development wells was estimated, and the effects of platform construction based on the location of exploration well on the drilling difficulty were analyzed.Finally, the platform location optimization technology based on the economic evaluation for the integrated exploration and development of middle and deep seated oilfields in the Bohai Sea was developed.In the exploration stage of Bohai A Oilfield, platform location was chosen between the location of detailed exploration well and the optimized platform location, and it was finally determined to build the platform based on the location of detailed exploration wells so as to convert the exploration investment into development investmenteffectively.The successful application of this technology in Bohai Sea proves the correctness of exploration-development integration concept.By virtue of this technology, the conversion of exploration investment into development investment is realized, and the development threshold of middle and deep seated oilfields is decreased.The research results provide the experience for the development of middle and deep seated oilfields in the future.