Bounded thin oil reservoir, which is characterized by less reserves, thin thickness, and weak energy of edge or bottom water, could hardly be developed with high cost, low recovery and high risk. Bajiaoting oil field, which is located in East China Offshore, has all the characteristics of bounded thin oil reservoir, what's more, it has low permeability: less than 10mD. As a result, it could not be developed without water injection wells, but water injection cases could not be taken in East China Offshore due to the restrictions of the producing platform. Face all the difficulties, Water Dumping, which could maintain pressure and improve recovery with low cost, was applied in Bajiaoting oil field, and it is the first time that this technology applied in China offshore. Traditionally, water injection wells are located in the edge of the reservoirs and oil wells are located in the centre area. By contrary, new case was put forward: transform the oil well which located in the center into water dumping well in the appropriate time. Therefore, dumping water could spread from edge to the center, and then, to the other edge. In this study, related calculation methods for pressure and injection rate are applied, and the effects and simulation results of some adjustment cases are discussed.